Neutral Citation Number: [2004] EWCA Civ 1249
Case No: B3/2003/1603
IN THE SUPREME COURT OF JUDICATURE
COURT OF APPEAL (CIVIL DIVISION)
ON APPEAL FROM 
HIS HONOUR JUDGE ALISTAIR MACDUFF

Royal Courts of Justice
Strand, London, WC2A 2LL

Date: 30th September 2004
Before :

THE RIGHT HONOURABLE LORD JUSTICE AULD
THE RIGHT HONOURABLE LORD JUSTICE SEDLEY
and
THE RIGHT HONOURABLE LORD JUSTICE KEENE
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Between :

	EXEL LOGISTICS LTD 	Appellant / Third Defendant	
	- and -		
	1) WAYNE CURRAN
2) LAND ROVER (UK) LTD
and
PAUL STIMPSON

	Respondents Second and Third/ Defendants

Claimant / Respondent 	

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Mr Christopher Sharp QC (instructed by Lyons Davidson) for the Appellant/Third Defendant
Mr Christopher Kennedy (instructed by Bott and Company) for the First and Second Respondents/ First and Second Defendants
Mr Allan Dooley (instructed by Blakemores) for the Claimant/Respondent

Hearing dates : 4th May 2004
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Judgment
Lord Justice Auld : 
1.	On 26th September 2004 Paul Stimpson, the claimant/respondent, was a passenger with nine others in Land Rover Defender 12 seater motor vehicle driven being by Wayne Curran, the first defendant/respondent, provided by Mr Curran’s employers, Land Rover (UK) Ltd., (“Land Rover”), the second defendant/respondent.  The Land Rover, which was equipped with power steering, was seemingly in immaculate condition and had been well maintained by Land Rover. The accident happened on the M6 motorway, when, about 40 miles into the journey, Mr Curran pulled out to overtake a bus.  As it was completing its overtaking movement the Land Rover swerved to its left and then to its right and rolled along the motorway before coming to rest on its roof, causing Mr Stimpson and other passengers serious injuries, in one case, fatal.  
2.	There were a number of alleged individual or contributory causes of the accident.  
3.	The first was the undoubted fact that the two rear tyres of the vehicle were seriously under-inflated when the party set off on their journey, rendering it unstable once it deviated from a straight line.  Land Rover acknowledged at the trial that it had been negligent in providing the vehicle with under-inflated rear tyres and that the under-inflation was a cause of the accident.  The Judge, His Hon. Judge MacDuff, so found.   
4.	There were three distinct allegations of negligence against Mr Curran, namely:  failure to check the pressures of the tyres before the party set off on its journey so as to discover the serious under-inflation of both rear tyres; failure to heed the under-inflation of the rear tyres in the course of the journey, which was or should have become apparent to him by its effect on the handling of the vehicle; and undertaking the overtaking movement in a negligent way, thereby precipitating the accident.  The Judge acquitted Mr Curran of all of those allegations of negligence.
5.	The final alleged cause, which was bound in with the allegation of negligent driving against Mr Curran, was the defective condition of the assembly of the front off-side tyre of the Land Rover, which, after the accident was found to have a split inner tube and to have become seriously deflated.  It was alleged on behalf of Mr Stimpson, Mr Curran and Land Rover that the split and resultant deflation had occurred in the course of the journey, thereby combining with the pre-existing instability of the under-inflated rear tyres to precipitate the accident..  Exel Logistics Ltd. (“Exel”), who had assembled the front off-side wheel and tyre and had provided it to Land Rover, acknowledged at the trial that it had fitted the tyre negligently by leaving dirt and grit between the inner tube and tyre-casing.  However, it denied that such negligence had been causative, either because, as it maintained, the inner tube did not split before the accident, but was caused by it, or, if it did split before the accident, because the deflation of the tube did not contribute to the accident. The Judge found that the split and partial deflation of the front offside tyre tube occurred before the accident and that, in combination with the seriously under-inflated tyres, caused it.  He held Exel to have been more blameworthy in its assembly of the front off-side tyre than Land Rover in its failure to maintain the pressures of the rear tyres at a proper level, and apportioned responsibility between them at two thirds/one third respectively. 
6.	Exel, with the leave of the Court, appeals the Judge’s acquittal of Mr Curran of negligence in the respects alleged at trial, the Judge’s finding of negligence against Exel that the deflating front off-side tyre contributed to the accident, and, if Exel is liable at all in negligence for the accident, the Judge’s apportionment of liability as between Land Rover and it. On the issue of apportionment Exel maintained that its liability should not exceed 50%, but should more appropriately be one-third or less.  There are thus three main issues: 1) the liability in negligence, if any, of Mr Curran; 2) the “initiating” cause of the accident; and 3) apportionment of liability as between those defendants who were liable.  
7.	The undisputed evidence before the Judge was that both rear tyres of the Land Rover were seriously under-inflated when the journey began, that this would have affected the handling of the vehicle when turning, and that it would have created a tendency for it to “over-steer” in the direction in which the vehicle was turned.  They were 29 psi when they should have been 48 psi.  As to the front tyres, it was common ground that the front off-side tyre was properly inflated at the start of the journey and no reason to suppose that its pressure would have been any different from that of the front near-side tyre after the accident, also 29 psi – about the recommended pressure for the front tyres.  But examination after the accident revealed a split in the inner tube of, and a seriously, deflated off-side tyre.  There was conflicting evidence as to whether it had deflated, substantially or at all, before the accident, so as to cause or contribute to it, or whether the accident caused the split in the tube and the deflation of the tyre.
8.	The Judge, in paragraphs 7 to 9 of his judgment, helpfully summarised the effect of the expert evidence on the phenomenon of “over-steer” produced by under-inflation of rear tyres of a vehicle.
“9.  … [The] under-inflation at the rear would undoubtedly have affected the handling of the vehicle.  There would have been a tendency for the vehicle to ‘over-steer’ in both directions.  Tyre pressures are designed to produce ‘under-steer’, that is to say make the steering respond in the natural way if the driver makes a minor error, for example, coming into a bend too quickly.  An under steered vehicle will tend to ‘flatten’ or ‘straighten’ the bend, so that the driver has to apply more steering lock to pull the vehicle into the bend and hold it there.  Thus the tyre ‘scrubs’ against the road and the speed is brought down in a safe controlled way.  Under steer is typically produced by setting the rear tyre pressures higher than the front pressures, in a rear wheel drive vehicle.  This is even more important in a heavily laden vehicle.
8.  Over steer produces the opposite effect.  If a driver enters a bend too fast, the vehicle tends to ‘tighten’ into the bend of its own accord and the driver has to prevent this by winding off the steering lock so as to steer in the opposite way to the bend.  In reducing the steering lock, the tyre scrub is reduced so that there is less retardation.  This may give the driver an impression that the vehicle ‘accelerated around the bend’.  In fact, the vehicle would not accelerate, but would slow down to a lesser extent than anticipated.
9.   Additionally, when negotiating a bend, there would be a feeling of instability, particularly at the rear end of the vehicle.  This would be most apparent to those seated at the very rear, …”
9.	The Judge also helpfully summarised the main undisputed evidence as to the nature of the accident itself.  During the journey, some, but not all, of the passengers noticed a feeling of instability in the form of some “wobbling” or “wallowing”, in particular, in two separate incidents.  The first was on the short journey onto the motorway when the vehicle negotiated a tight roundabout, and one on the motorway, shortly before the accident when they were overtaking a lorry.  As the Judge observed, by reference to the expert evidence before him, such instability was how a vehicle with under-inflated rear tyres would behave. 
10.	As I have said, the accident occurred when Mr Curran was overtaking a coach.  On Mr Curran’s account, he began to feel difficulty in controlling the vehicle when he was alongside the coach.  He said that as he got nearer the front of it he had a feeling of being “sucked in” towards it, and had to struggle with the steering wheel to prevent a side to side collision.  From his and other evidence, as he cleared the front of the coach the Land Rover made a sharp left turn, such that that the coach driver thought he was being “cut up”.  The Land Rover then “snaked” or fish-tailed”, causing it to rock between its near-side and off-side wheels, before rolling over along the carriageway and coming to rest on its roof.
Issue 1 – Causative negligence of Mr Curran? 
11.	As I have indicated, there were three respects in which it was suggested at trial that Mr Curran was negligently responsible for the accident: 1) failure to check tyre pressures before setting out on the journey; 2) failure to notice or heed the unstable condition of the vehicle; and 3) driving error.   The third of those issues is bound up with that of the failure of the front off-side tyre and its causative effect, if any. 
 (a) failure to check tyre pressures.
12.	As I have said, the Judge found that Mr Curran had not been negligent in not checking the pressures of the rear tyres before setting off on the fateful journey.  He said that he found him to be a frank and impressive witness, whose evidence on this and all other issues concerning him he accepted.
13.	The Land Rover was a company vehicle owned and maintained by Land Rover, and, seemingly, in immaculate condition.  Mr Curran was an employee of Land Rover, but was not acting as such on this occasion.  He said that he had not seen any written instruction of Land Rover, but that he knew the employee of Land Rover responsible for the vehicle and that he was very conscientious about its care.  Nevertheless, Mr Curran volunteered, when giving evidence, that he regarded it to have been his responsibility to have checked the tyres before setting out on the journey. 
14.	The Judge, applying the test of the reasonable man, observed, at paragraph 74 of his judgment, that very few people taking possession of an immaculate vehicle from Land Rover, knowing it to be a company car, would have thought to check its tyre pressures before setting off in it:
“…  I have reached the conclusion that, notwithstanding … [Mr Curran’s] frank admissions, it was not unreasonable in all those circumstances to rely upon the fact that the vehicle was so obviously well maintained, and in good condition.  Perhaps that can be put in another way; it was not reasonably foreseeable (any more than when one takes possession of a new car from the car showroom of a main dealer) that the tyres would be at dangerous under inflation.  In my judgment, … [Mr Curran’s] failure to check tyre pressures fell short of hard negligence.  He did no more and no less than the vast majority of people would have done.  His actions measured up to the actions of the reasonable man.”
15.	Mr Christopher Sharp QC, on behalf of Exel, submitted that Mr Curran owed a duty of care to his passengers, that it included a duty to check the tyres before setting out on the journey and that, if he had done so, he would have seen that both rear tyres were seriously under-inflated.  He challenged the Judge’s ruling that there was no duty on Mr Curran in the circumstances to check the tyres.
16.	First, Mr Sharp submitted that there was an obligation in law, which Mr Curran had accepted in evidence, to ensure that the pressure of the tyres was sufficient for the vehicle to be safe.   He referred to regulation 27(1)(b) of the Road Vehicles (Construction and Use) Regulations 1986, not to use a vehicle on a road if its tyres are not so inflated as to be fit for use, breach of which is an absolute offence under section 41A of the Road Traffic Act 1988.  He acknowledged that such breach did not of itself give rise to a cause of action, but submitted that it “highlight[ed] the obligation from which the court … [could] infer a duty of care when, as here, the driver had been in a position to do something about it.”   
17.	In so submitting, Mr Sharp relied on observations of this Court in Franklin v The Gramophone Company Ltd [1948] 1 KB 542, CA, in holding that compliance with statutory obligations, which may be of limited scope, do not necessarily absolve a defendant from liability in negligence.  He referred particularly to passages in Scott and Somervell LJJs’ judgments, at pp. 552 and 558 respectively, and of the Judicial Committee of the Privy Council in Tan Chye Choo & Ors v Chong Kew Moi [1970] 1 All ER, at 272f-g, that statutory obligations may indicate a standard of care, breach of which would be evidence of negligence.  However, as both citations make clear, it all depends on the width of the statutory obligation in question.  He suggested that regulation 27(1)(b) set the standard of care for this purpose.  But, in response to the Court’s indication that the width or level of statutory duty that it created was wide enough to establish an absolute duty regardless of any degree of blameworthiness, he returned to the more conventional argument that the risk of dangerous over-steer flowing from under-inflated rear tyres imposed a high standard of care on Mr Curran in the circumstances. 
18.	Second, Mr Sharp relied on Mr Curran’s acceptance that he had known the importance of correct inflation of  the tyres, especially when driving at speed with a full load on a motorway, and that he should have known the recommended pressures for the Land Rover and should have checked them before setting out.
19.	Third, Mr Sharp referred to the evidence of Mr Stimpson’s and Land Rover’s experts, Mr Grogan and Mr Newland respectively, that type pressures should be checked always before setting out, especially if, as here, the load was unusual for the vehicle.
20.	Fourth, Mr Sharp drew attention to the fact that Mr Curran was not familiar with this particular vehicle or with Land Rover’s procedures for its maintenance and could not, therefore, claim to have had sufficient knowledge of its use and condition to justify a failure to check the pressures.  He added that, in any event, Mr Curran did not claim to have relied upon Land Rover’s maintenance of the vehicle as a reason for not checking the tyres.
21.	Accordingly, Mr Sharp submitted, there was no evidential basis for the Judge’s finding that it was reasonable for Mr Curran to have relied upon the condition and maintenance of the vehicle.  And, even if there had been such a basis, the risk to his passengers when balanced against the smallness of the task of making a check was such that failure to check was still unreasonable. 
22.	Mr Christopher Kennedy, on behalf of Mr Curran and Land Rover, relied on the Judge’s reasoning for absolving Mr Curran of negligence in not checking the tyre pressures, and on the observation of Rix LJ, with whom Carnwath LJ agreed, in granting permission to appeal, that it was “robust common sense”.  He stressed the Judge’s findings of fact that the vehicle was seemingly in immaculate condition and part of the Land Rover fleet maintained by Land Rover.  There was, therefore, he said, nothing to suggest to Mr Curran that the tyres were not set at the appropriate pressure.  
23.	As to Mr Sharp’s reliance on regulation 27(1)(b)  of the 1986 Regulations, Mr Kennedy pointed out that it creates an absolute obligation, and, if breached, is an offence of strict liability.  It is, therefore, not indicative of, or relevant to, the claim that Mr Curran was negligent in this respect.  In any event, he submitted, a breach of the regulation does not give rise to an action for damages, relying on a number of rulings of the courts in relation to similar regulations under the Road Traffic Acts, most notably Phillips v. Britannia Hygienic Laundry Co Ltd [1923] 2 KB 832, CA.
24.	Mr Kennedy submitted, correctly in my view, that neither Mr Curran’s acceptance that he should have checked the tyres before setting out nor the views of the experts that he should have done so, in any way, bound the Judge on this issue, which is a matter of law.   As Mr Kennedy observed, Mr Curran might have blamed himself for not taking a step, which, with hindsight, could have avoided this terrible accident, but that sentiment does not fix him with liability in negligence.  As to the experts, their expertise was as to the behaviour of tyres, not as to the practice of the reasonable and prudent motorist, which was essentially a matter for the Judge.  And, as to the complaint that that Mr Curran could not rely on Land Rover’s maintenance procedures because he had no detailed knowledge of them, Mr Kennedy said the presence or absence of such detailed knowledge was irrelevant; it was enough that he knew that it was one of a fleet of vehicles provided by such a large and reputable organisation.  
25.	I should first deal with the argument of Mr Sharp as to the relevance of regulation 27(1)(b) of the 1986 Regulations.  First, in its creation of an absolute duty, it can be of no guidance, in the way in which the statutory obligation under consideration in Franklin was, namely as to the standard of duty of care applicable in the circumstances.  Second, even if it were, it would not afford an individual a private right of action, as this Court held in Phillips v Britannia Hygienic Laundry in relation to a provision under the Motor Cars (Use and Construction) Order 1904, which required a motor car and all its fittings to be “in such a condition as not to cause, or be likely to cause, danger to any person on the motor car or on any highway”; see per Atkin LJ at 842; see also Tan Chye Choo & Ors v. Chong Kew Moi, at 270d et seq. (Motor Vehicles (Construction and Use) Rules (Malaysia)); Coote & Anor v Stone [1971] 1 All E R 657, CA (Various Trunk Roads (Prohibition of Waiting) (Clearways) Order 1960).
26.	Second, Mr Curran’s acceptance in evidence that he should have checked the tyres cannot fix him in law with negligence in that respect.  Nor can the views of the experts, if and to the extent that they were directed at all to the issue of civil law liability for failure to check, since they were not part of their expertise.  Their role was to speak as to the performance of tyres, not on legal obligations relating to their assembly or maintenance.
27.	For the reasons I have given, the Judge’s application of “the reasonable man” test was in no way vitiated by the existence of the statutory absolute duty in the 1986 Regulations, which prompted Rix and Carnwath LJJ to give permission.  In the real world, that in which the man on the Clapham omnibus used to operate, nobody would sensibly suggest that Mr Curran should have checked the correct tyre pressures of a company vehicle, seemingly in immaculate condition and, which he knew, was maintained by a Land Rover employee who was highly conscientious about the condition of the vehicle.  I can see no basis on which the Court could disturb the Judge’s finding on this issue.
 (b) failure to notice or heed the  unstable condition of the vehicle 
28.	Rix and Carnwath LJJ refused permission to appeal on this point, but, because, we considered that all the issues should be considered together, we granted permission and Mr Sharp argued it.   Mr Curran’s evidence, which, on this as on other issues, the Judge accepted, was that he had noticed no problems with the handling of the Land Rover until he was in the act of overtaking the coach.  All that he had noticed was a slight “buffeting” which he took to have been caused by wind resistance when he overtook a lorry earlier on the motorway.   The Judge found, at paragraph 69 of his judgment, that, on the evidence before him, there had been nothing to put Mr Curran on notice that the Land Rover was not handling properly; none of his passengers had asked him to slow down, several of them, particularly, those in the front, had not sensed anything amiss on either of two “wobbling” or “wallowing” incidents which others, mostly in the rear of the vehicle, had mentioned (see paragraph 9 above).
29.	In my view, given the Judge’s finding, there is again no basis on which this Court could intervene to find that Mr Curran should have been put on notice by the two previous incidents to which only some of his passengers referred.  It is plain that, on his own account, which the Judge accepted, his journey on the motorway, following a straight line and overtaking gradually in the way one does on motorways, had caused him no difficulty in managing the vehicle or reason to suspect the underlying instability awaiting him if he was forced to move suddenly to the right or the left. 
Issue 2 – The immediate cause of the accident, driving error and/or failure of the front off-side tyre
( a ) driving error
30.	The evidence as to the accident itself consisted largely of the evidence of Mr Curran, the coach driver, Mr McElroy, and the witness statements of two passengers, Mr and Mrs Gemmell, sitting in the front of the coach.  The other passengers in the Land Rover, for one reason or another, were of little assistance.  As I have said, the Judge accepted Mr Curran’s evidence on this as on other issues.  
31.	Mr Curran’s account, which was largely supported by the evidence of Mr McElroy and Mr and Mrs Gemmell, was that it was when he was level with the coach that he first experienced difficulty in controlling the Land Rover, causing him to swerve.  He could not remember, no doubt because of the agony of the moment,  whether the first movement or pull of the vehicle was to the left or to the right, though Mr McElroy and Mr and Mrs Gemmell all spoke of the Land Rover first swerving to the left as it passed in front of the coach.  The Judge, in paragraph 26 of his judgment, said of Mr Curran’s evidence on this point:
“The picture which presented itself to me was of … [Mr Curran] fighting with the controls to avoid moving to the nearside and into contact with the coach, and, at the same time, fighting to avoid steering too far to the right, so as to lose control that way.  He did indeed manage to avoid colliding with the coach, and got clear of it, before there was a sudden veering to the left (in front of the coach) after which the Land Rover began to ‘fishtail’, rocking from nearside wheels to offside wheel, before cart wheeling out of control and bouncing on its roof, rolling along the motorway, in front of the coach.”
32.	As the Judge observed, at paragraph 69 of his judgment, the suggestion that Mr Curran caused the accident by losing control of the vehicle through driver error was part and parcel of Exel’s case that the front off-side tyre had not deflated before the accident or that, even if it had deflated, had not been a cause of it.  The Judge, as I have said, rejected this suggestion, holding that the loss of control was entirely due to the unsafe condition of the tyres, the front off-side tyre precipitating the “fish-tailing”, exacerbated by the condition of the rear tyres, and that there was nothing that Mr Curran could have done to prevent the accident .
(b) failure of the front off-side tyre
33.	The Judge regarded as “the nub of the case” whether the front off-side tyre deflated before, so as to cause the accident, or during it and as a consequence of it.
34.	Before I turn briefly to the evidence of the experts, I should emphasise, as the Judge did, that it was common ground between them that a seriously deflated front off-side tyre would not normally affect the handling of a vehicle when being driven in a straight line or when turning to the right.  It is normally only when a driver is turning to the left that it causes difficulty.  The Judge, in the following summary, at paragraph 36 of his judgment, of the experts’ agreement about this, helpfully explained the mechanics - and the dilemma for Mr Curran and Land Rover - that the evidence pointed to an initial move to the left, not to the right:
“Thus, it is not surprising that on a motorway, in light traffic (the uncontested evidence is that … traffic was very light) a gradually deflating tyre could go unnoticed by the driver, given that only gradual adjustments of direction would be necessary; there would be no need to change direction suddenly, and there would be no tight cornering.  As … [Mr Curran] pulled out to overtake, the nearside tyres would be doing the work, and there would no tendency to deviate.  However, as he straightened up in the centre lane, he would, in effect be making a slight left turn and the offside tyre would be put to work.  The tendency would be to tangent off to the right.  It is clear that … [Mr] Curran had succeeded in establishing his position in the centre lane behind the coach, and moving forwards in a straight or virtually straight line.  At this point, there should have been no inclination for the vehicle to deviate, even if we assume that the front offside tyre was indeed substantially under inflated.  The problem, in theory, would not arise until the moment when the driver tried to steer to the left, presumably to move back in front of the coach.  This, of course, would put the failing tyre on the outside of the arc, and the tendency would be for the initial movement of the vehicle to be to the right.  Here, the eye witness evidence described a movement not to the right, but to the left. …”
35.	Mr Grogan, the expert tyre consultant instructed, as I have said, on behalf of Mr Stimpson, had examined the front off-side wheel on behalf of the police after the accident.  He attributed the split to abrasion of the inner tube, caused by grit or dirt found in the inside of the tyre having been lodged between the tube and the tyre-inner wall, and to increasing movement between the two as a result of deflation of the tube. There were signs of recent grooving and polishing of tyre beads against the wheel flange, which, Mr Grogan, and also Mr Newland, the expert instructed on behalf of Mr Curran and Land Rover, said, indicated movement between the tyre and its tube within the tyre while in motion. They were of the view that it had occurred during a short period of moderate under-inflation, namely within tens, not hundreds, of miles. It was, as  I have said, accepted by Exel that it had negligently allowed such foreign material to remain within the tyre when it fitted it. That, with the evidence of the recent grooving and polishing of the tyre beads against the wheel flange, led Mr Grogan and Mr Newland to deduce that the tube must have been close to the point of failure at the start of the journey and that during it a small breach developed, leading to gradual and accelerating deflation as the split became larger.   Whilst they allowed that the tube could have failed as a result of the accident impact, they considered it unlikely.  They were of the view that that failure of the front-offside tyre during the course of the journey was the precipitating, or initiating, cause of the accident, which, together with the seriously under-inflated rear tyres provided the “lethal cocktail” causing Mr Curran to lose control of the vehicle when and in the way he did.  The Judge said that he found the evidence of both Mr Grogan and Mr Newland impressive.
36.	Mr Price, the expert called on behalf of Exel, disagreed.  However, he did so after some changes of mind from opinions expressed in his original report.  He said that the initial leftward movement of the Land Rover after it had overtaken the coach was not what he would attribute to a deflated front off-side tyre; there would have to have been some other cause, such as a “slipstream” effect.  He suggested for the first time in the witness box that the grooving of the tyre bead against the wheel flange had occurred over hundreds of miles so as to indicate that the tyre had been running under-inflated in the past and/or throughout the journey as a result of lack of maintenance.  He suggested, more firmly than he had in his report and contribution to joint experts’ statements, that there had been no movement to the right when Mr Curran lost control and that the accident caused the front off-side tyre to fail rather than the other way round. 
37.	The Judge said that he found Mr Price to be an unsatisfactory witness; his evidence lacked objectivity; he appeared to see his role as an advocate for Exel, and he frequently descended into the arena.  The Judge said that wherever his evidence coincided with that of Messrs Grogan and Newland, he accepted it.  Where it differed, he rejected it.
38.	The Judge found, at paragraph 47 of his judgment, that the expert evidence clearly established that the front offside tyre had been leaking air during the course of the journey as a result of Exel’s negligent assembly of the tyre; that the speed of leakage accelerated as the journey progressed and that the split in the tube grew so that the tyre became seriously deflated; and that, in that condition, it would have made the vehicle unmanageable once a loss of control had begun to occur.
39.	But there remained the matter on which Exel relied, the absence of evidence of a pull, swerve or other movement to the right indicative of the effect of a severely under-inflated, or final failure of a front off-side tyre.  At paragraph 48 of his judgment, the Judge responded to what Mr Sharp called this “missing link in the chain”, by referring to the expert evidence on which he had found that the tyre had failed before the accident and to the “the totality” of the evidence that the substantially deflated tyre was the precipitating cause of Mr Curran’s loss of control.   He took account of the under-inflation of the rear tyres and its adverse effect on the handling of the vehicle.  However, given the relatively uneventful passage of the journey over some forty miles with the rear tyres in such condition, he considered that their condition, on its own, could not have been responsible for the accident.  The precipitating cause, he held was the development of the substantial under-inflation of the front off-side tyre, which, he held, “on any view, would be likely to cause sudden instability and loss of control”.  
40.	The Judge considered that, on a balance of probabilities, there was no other sensible explanation.  He rejected the suggestion that driving error by Mr Curran on this simple manoeuvre on a straight stretch of motorway, coupled with the under-inflated rear tyres, could have caused him to lose control of the vehicle in the way he did.  He acknowledged that the absence of any pull to the right immediately before the accident was “maybe” a missing piece of the jigsaw, but concluded that all the other pieces were there and that, even without the  last piece of the jigsaw, “the picture … [was] obvious and there to be seen”.  Nevertheless, he looked for a possible explanation for the absence of evidence of an initial rightwards movement, and, at paragraphs 53 and 54 of his judgment, referred to possibilities which, as it happened, Mr Price had raised in paragraph 4.16 of his report:
“53. … There may be several possible explanations.  It may be that, as the Land Rover was alongside the coach, and as … [Mr Curran] made some adjustment to his steering (presumably to the left) there was indeed an uncovenanted movement to the right, which would cause … [Mr Curran] to steer to the left, producing a swerve in that direction.  It may be that, in the agony of the moment, he was unaware of the precise sequence of events, and replaying it in his memory, parts were not recalled.  It may be that the under inflated rear tyres exacerbated the problem by causing over steer as …[Mr] Curran adjusted the steering first one way and then the other.  It may be that there was some ‘slipstream’ effect alongside the coach.  It may be that the impression was given that he was being ‘sucked in’ by the coach, when in fact it was his own steering (to counter the pull to the right) which caused the movement to the left, accentuated by the low pressure in the rear tyres, and the over steer which would result.  
54.  Ironically, Mr Price touched upon this in paragraph 4.16 of his report …  However, what is unknown, are the actions of the driver if the tyre deflated before he lost control of the vehicle.  It is therefore possible that the front offside tyre did deflate in use and he made some ineffective manoeuvres.  In these circumstances, instability would have resulted from a combination of the manoeuvres, the seriously under inflated rear tyres, the nature of the vehicle and the load being articulated’.  I agree with that, if Mr Price was saying (as I understand it to be) that, with a combination of all those factors, including the unknown reactions of the driver and the combination of rear tyres pushing the vehicle one way, as the failing front tyre would tend to push the other way, it becomes impossible to predict with confidence what would or might happen to the vehicle.  To that I add this; in my opinion, it is just not possible to rely upon the evidence of the driver, and to expect him to give reliable evidence as to whether the first movement was to left or right (for example) in the agony of the moment.   … power steering … would potentially produce another unknown.  As the experts all agreed (and this was expressly the evidence of Mr Price himself) the effect of power steering would be to enable the driver more easily to override any pull to the right.”
41.	The Judge concluded his examination of this issue in the following terms in paragraph 55 of his judgment:
“The precipitating cause of this catastrophic accident was, I find, the defective front offside tyre, which, at the time of the accident, had deflated to approximately half its proper pressure, and created huge instability.  A loss of control on the part of the driver was virtually inevitable.  As the experts agreed, the under inflated rear tyres did not instigate the accident sequence …, but, as I find, made a significant causative contribution.  The initial loss of control was caused by the loss of pressure in the front offside tyre, but the subsequent events, snaking, rocking between offside and nearside wheels, and subsequent spin and roll were, in large part, the result of over steer and rear  tyre under inflation.”
( c ) Submissions as to the immediate cause of the accident.
42.	Mr Sharp submitted that the Judge failed to consider, or to consider sufficiently, the possibility of Mr Curran having driven too close to the coach as he was overtaking it and, as a result having been pulled towards it.  He pointed to passages in Mr Curran’s evidence of having felt as if the Land Rover was being pulled to the left as he was alongside the coach.  He also drew attention to the evidence of Mr Grogan that, if Mr Curran had driven too close to the coach and been pulled towards it, the over-steer from the under inflated back tyres could have caused instability, sufficient, in Mr Sharp’s submission to have precipitated the loss of control, to which any defect in the front off side tyre would have been no more than a contributory factor.  
43.	As to the front off-side tyre, Mr Sharp submitted that there was no sufficient evidence of its failure before the accident, or that if there was, there was no evidence of its causative effect.  He maintained that the Judge wrongly absolved Mr Curran of negligent driving largely because of his finding as a fact that the initiating cause of the accident was the failure of the front off-side tyre due to a split in the abraded inner tube.  He complained, in particular, that the Judge failed sufficiently to take into account that: 1) there was no evidential support for Mr Grogan’s and Mr Newland’s conclusion that the front off-side tyre was seriously under-inflated immediately before the accident and that such under-inflation caused Mr Curran’s loss of control; 2) there was no evidence of any initial move of the Land Rover to the right, which all the expert evidence indicated would have been the likely consequence of a failure in the front off-side tyre; and 3) there was no  evidence to support the Judge’s “speculation” in paragraphs 43 and  53 of his judgment of Mr Curran having subconsciously steered to the right to counter a pull to the left.
44.	Mr Kennedy relied on the Judge’s reasoning, in particular, his stress on the whole picture and his characterisation of his task as piecing together a jigsaw.  He drew particular attention to his finding that that Mr Curran had not caused the accident by negligent driving, and Mr Grogan’s and Mr Newland’s evidence that the front off-side tyre had begun to fail during the journey. 
45.	As to the absence of evidence of any negligent driving by Mr Curran, Mr Kennedy relied on the Judge’s acceptance of his evidence that he had experienced no problem with the control of the vehicle throughout the journey, that he had not driven too close to the coach when overtaking it, and the absence of any evidence that he had initiated any manoeuvre of a kind that could have led to his loss of control of the vehicle.  He submitted that the Judge correctly found on the evidence that Mr Curran had not caused or initiated the accident by any negligent act of driving. 
46.	As to Mr Sharp’s suggestion that Messrs Grogan and Newland had no evidential basis for their conclusion that the front off-side tyre began to fail during the journey, Mr Kennedy pointed to their evidence of their respective examinations of the tyre and analyses. 
47.	Mr Kennedy said that the Judge, faced with those two conclusions, had to and did consider what else other than the progressive deflation of the front off-side tyre could have caused Mr Curran’s sudden loss of control as he overtook the coach.  He said that the Judge, like Messrs Grogan and Newland, was alive to, and grappled with, the fact and possible significance of the vehicle not having initially moved to the right immediately before the loss of control leading to the accident.   He noted that, although those two experts considered the absence of evidence of a move to the right merited mention, neither considered that it undermined his opinion that the progressive deflation of the tyre caused or contributed to the accident. He submitted that, once the Judge had found that the deflation of the front off-side tyre was not just a coincidence, but a factor relevant to the loss of control, he was entitled to conclude, on all the evidence, that it was causative of the loss of control.  He referred, in particular, to the Judge’s reasoning that the lack of any evidence of a discrete move to the right was possibly explicable for the reasons that he gave in paragraphs 53 and 54 of his judgment, namely the unquantifiable effect of instinctive and unconscious reactions of Mr Curran in the agony of the moment coupled with the power-steering with which the vehicle was equipped. 
48.	Mr Allan Dooley, on behalf of Mr Stimpson, supported the Judge’s findings as to Exel’s causative negligence on essentially the same grounds as those advanced by Mr Kennedy.  He added that the evidence of Mr Grogan of the tendency of a vehicle to move to the right on the deflation of a front off-side tyre was just that - a tendency - it was not invariable, as Mr Grogan’s evidence of earlier work on such a phenomenon had shown. 
(d) Conclusions as to the immediate cause of the accident.
49.	As I have said, it was common ground among the experts that the under-inflation of the rear tyres, the level of which was constant, not progressive, through a serious threat to the stability of the vehicle, would not have caused a problem unless and until there was a sharp movement to the right or left, in which event it could have produced dangerous over-steer.  Given the Judge’s acceptance that Mr Curran had not driven too close to the coach or otherwise negligently so as to cause the loss of control, the only candidate for some sideways movement, one way or the other, bringing into play the feature of instability flowing from the under-inflated rear tyres was failure of the off-side front tyre.  He found, on Messrs Grogan’s and Newland’s evidence, that such failure precipitated the fish-tailing and over-turning of the vehicle, and did not result from such acrobatics. 
50.	In my view, the Judge was entitled, on the evidence and for the reasons he gave, to find that such a failure of the front off-side tyre, had given life to the, thus far, latent serious instability created by the dangerously under-inflated rear tyres.  As Mr Grogan observed in evidence, “something clearly changed in the last manoeuvre to produce that loss of control, which was nowhere apparent before that.” And, as Mr Dooley submitted, the Judge’s finding that the gradually deflating front offside tyre, would have caused sudden instability was consistent with the expert evidence, namely that the effect was likely to be sudden when the progressive deflation reached a critical point and a manoeuvre right or left was undertaken.  And, as Mr Dooley also observed, Mr Sharp’s argument on this issue was based on one limited assertion, namely that there was no evidence of the Land Rover pulling to the right in an involuntary manner.  For the reasons given by the Judge in paragraphs 53 and 54 of his judgment, that proposition is itself open to doubt.  It is also against the weight of the rest of the evidence.  
51.	The Judge’s consideration of possibilities as to why an initial right hand pull or movement was not evident in this case, was not, as Mr Sharp suggested, one of deciding the case on speculation or on a balance of improbabilities, as the House of Lords held Rhesa Shipping Co. SA v Edmunds [1985] 1 WLR 948, HL, Bingham J, as he then was, had uncharacteristically done in that case.  The suggested conflicting improbabilities here, on Mr Sharp’s hypothesis, were an otherwise inexplicable move to the left and the possible, but unlikely failure of the inner tube due to the impact of the accident itself.   Given the Judge’s acceptance of Mr Curran’s evidence and the expert views of Messrs Grogan and Newlands as to the mechanics and timing of failure of the front off-side tyre, his reasoning at paragraphs 49 to 55 of his judgment, read properly and together, clearly indicate a finding of negligence against Exel on a balance of probabilities, not improbabilities.  Accordingly, I would uphold the Judge’s finding that Exel’s negligent assembly of the front off-side tyre and inner tube was both negligent and a cause of the accident.  
Issue 3- Apportionment
52.	The main thrust of Mr Sharp’s argument before the Judge was that if the rear tyres had been properly inflated the accident would have been less serious because the likelihood was that the vehicle would not have overturned. The Judge, at paragraph 76 of his judgment, rejected that argument for two reasons.  First, he said that it overlooked the fact that, if the front off-side tyre had not failed, the accident would not have happened at all.  And second, he said, Exel’s negligent assembly of the wheel and tyre so as to cause the inner tube to degrade and eventually fail, was more blameworthy than the failure fully to inflate the rear tyres.  In the result, he found, as I have mentioned, Land Rover liable for one third of the damages to be awarded to Mr Stimpson and Exel for two thirds.
53.	As I have said, Land Rover admitted, and the Judge found, that it had been causatively negligent in permitting the Land Rover to set out on the journey with its rear tyres dangerously under-inflated.  The Judge, at paragraphs 55 and 70 of his judgment, respectively found the under-inflation to have “made significant causative contribution” to, and to have been “a significant cause” of the accident.  He clearly accepted the evidence of Mr Grogan that, if the rear tyres had been properly inflated, there would have been a different and less serious accident.  If the deflated or deflating front off-side tyre had been the only defect, the vehicle would probably have moved out of control towards the right eventually coming to a stop against or close to the central barrier.  There would not have been the “snaking” or “fish-tailing” leading to the rocking and, ultimately, cart-wheeling of the vehicle.  He found that it was the “lethal cocktail” of the two defects that caused the accident.  
54.	Mr Sharp prefaced his submissions to the Court on this issue by noting that it is concerned with the causative potency matters giving rise to the result of the accident, not just to the accident itself, relying on the observation of Lord Reid to that effect in Stapley v Gypsum Mines Ltd 1953] AC 663, at 682, and of the judgment of Simon Brown J (as he then was) in Madden v Quirk [1989] 1 WLR 702. He said that the essential question was what as to the proximate cause of the damage, and submitted that it was Land Rover’s failure, knowing the danger of under-inflated rear wheel tyre pressures, to maintain proper levels of inflation.  He maintained, therefore, that Land Rover should attract all or the major part of the blame.  
55.	Mr Sharp submitted, by reference to the experts’ evidence that a combination of reduced rear tyre pressures and that of the front off-side (if it was reduced) would increase the severity of a turn to the right (if there was one) away from the coach and that, thereafter, the veering and snaking would be consistent with the inadequate rear tyre pressures.  Mr Sharp submitted that, put at its highest, the evidence was not that the initiating factor was the front off-side tyre, but that whatever sucked the Land Rover left towards the coach.  Accordingly, if the front off-side tyre was deflated or deflating, although it would have contributed to any over-steer to the right, such over-steer and thereafter the veering and snaking leading to the accident would have been largely attributable to the condition of the rear tyres.  He referred to Mr Grogan’s evidence of the “very significant effect” they would have had, once there was any deviation from a straight line, evidence to which, he submitted, the Judge gave insufficient weight.   On that basis Mr Sharp maintained that, at worst for Exel, it was equal in blame to Land Rover; but the main thrust of his argument was that the causative potency of its blameworthiness, even if the front off-side tyre was an initiating factor, was significantly less than that of Land Rover.
56.	Mr Kennedy supported the Judge’s apportionment and his reasoning for it.  He submitted in particular that the Judge properly considered the respective blameworthiness as well as the causative potency of the acts of the respective defendants.  He pointed to the Judge’s finding that the failure of the front off-side tyre was the initiating factor that brought into being the “lethal cocktail” of that failure and the dangerously under-inflated rear tyres.  As to blameworthiness, he said that the Judge clearly had in mind, in paragraph 76 of his judgment, a systemic failure of Exel’s processes, a failure that Exel had called no evidence to explain. 
57.	Mr Dooley made no submissions as to apportionment.
58.	I acknowledge that the Court, when considering a trial judge’s decision on apportionment, should normally allow him a wide margin of judgment or, as it is sometimes called, discretion.  However, although Mr Grogan and Mr Price agreed that rear tyre pressures alone could not have caused loss of control and there was, therefore, not a problem so long as the vehicle continued in a straight line, there was bound to come a time on a journey such as this when a significant turn to the right or left at some speed could bring the problem to life.  And, at that moment, as Mr Grogan testified, the consequence of under-inflated rear tyres – namely dangerous instability - is far more serious than any previous under-inflation of one or both front tyres.  However, if the precipitating cause of such a turn, as the Judge found in this case, was the failure of the off-side front tyre, thereby creating a “lethal cocktail” for activation of that dangerous instability from the rear, it is, in my view, hard to choose between the “causative potency” of the activating or precipitating cause and that of the dangerous and underlying instability at the rear to which it gave life.  Equally, looked at as a matter of blameworthiness for the consequences of the accident, it is hard to choose between Land Rover’s failure to maintain the rear tyres at the proper pressure, knowing, as it did, the possibly serious consequences of such failure, and Exel’s unexplained and egregious error in assembly of the front off-side tyre and inner tube in a condition which was highly likely to lead to sudden failure and, at least, the beginning of dangerous loss of control.   In the result, I agree with Mr Sharp that, in the circumstances, Exel should not be regarded as twice as much to blame as Land Rover for this accident and its serious consequences.  The causative negligence of each was substantial, and I can see no intellectually respectable basis for distinguishing between their respective blameworthiness.  I would, therefore, hold them equally to blame.  To that extent only, I would allow the appeal. 
Lord Justice Sedley:
59.	1 agree.
Lord Justice Keene:
60.	I also agree.
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