The court has given useful guidance of the circumstances in which a contractor will be liable in negligence for damage caused to third party property as a consequence of the defective works of its sub-contractors, and the circumstances in which a contractor will have a "non-delegable duty" to prevent such loss and damage.
The Claimant contractor, Willmot Dixon, appointed the Defendant engineer, RWC, to design the underpinning of a gable party wall at a property in Clapham, London. Willmott Dixon alleged that RWC's design was defective, had caused damage to the party wall and that, as a consequence, the project had been delayed, resulting in loss and damage. RWC contended that the damage to the third party wall had been caused or contributed to by the negligence of Willmott Dixon's sub-contractor, who had been carrying out work in and around the party wall.
Just before the trial of the action RWC applied to amend its Defence. It sought to delete the previously pleaded contention that Willmott Dixon was liable (under the exception set out in D&F Estates v Church Commissioners for England  AC 177) for the losses of its sub-contractor on the basis that it was aware that the sub-contractor was carrying out its works in a dangerous manner. It wished to delete the previously pleaded statement that "…for the avoidance of doubt, it is not alleged that [Willmott Dixon] was vicariously liable for [its sub-contractor's] negligent acts or omissions". Instead, RWC contended that Willmott Dixon owed a non-delegable duty for the losses suffered.
The court had to consider whether to permit the late amendments in RWC's case. In doing so, it stressed that the court needed to consider whether:
The amendments raised an arguable claim in law. That question gave rise to two sub-issues, namely (a) did Willmott Dixon owe a non-delegable duty in respect of the underpinning works carried out by its sub-contractor, and (b) if so, was that duty capable of being relied upon by RWC in its allegations of contributory negligence?
If so, was there a good reason for the delay in the application to amend and should the court exercise its discretion to allow the pleading?
RWC claimed that Willmott Dixon owed two non-delegable duties: first a duty to ensure to prevent loss and damages in circumstances where its sub-contractor was engaged in "extra-hazardous or inherently dangerous operations"; the second to prevent damage to adjoining property caused by the withdrawal of support by works undertaken on site.
Mr Justice Coulson refused permission to delete the words "…for the avoidance of doubt, it is not alleged that [Willmott Dixon] was vicariously liable for [its sub-contractor's] negligent acts or omissions". It was held that it was settled law (relying upon the speech of Lord Sumption in Woodland v Essex County Council  UKSC 66) that there could be no vicarious liability for the acts and omissions of an independent contractor. The real question was whether Willmott Dixon owed a non-delegable duty to avoid the damage suffered.
Mr Justice Coulson noted the difficulty in applying a test that placed contractors under a non-delegable duty in situations where works were said to be inherently dangerous. Importantly for contractors, Mr Justice Coulson decided, citing the Court of Appeal decision in Biffa v Maschinenfabrik  QB 725, that much in life can be said to be inherently dangerous. In order for a non-delegable duty to arise, the activities carried out must be exceptionally or unusually dangerous, no matter what precautions are taken. Applying that test, Willmott Dixon did not owe a non-delegable duty in carrying out the underpinning works.
However, the judge held that a non-delegable duty could arise in the context of the removal of rights of support, but only between owners of neighbouring land. As Willmott Dixon was not the owner of the property this duty to the adjoining landowner could not arise.
The judge's conclusions on these issues disposed of the application to amend. Nevertheless, he went onto consider the position on the basis that he was wrong in his judgment that the main contractor did not owe a non-delegable duty to procure the careful performance of the underpinning work. The question to be considered was whether this non-delegable duty was relevant to an allegation of contributory negligence by the Defendant engineer against the Claimant?
The decision was that the existence of such a duty was not relevant to contributory negligence. Mr Justice Coulson held that "what matters [when considering the question of whether there has been contributory negligence] is the claimant's failure to take reasonable care to look after itself; that would not involve some form of strict liability/non-delegable duty owed to others arising out of [the sub-contractor's] acts or omissions". In addition, if there had been a non-delegable duty it would not have been owed to the Defendant but to the owner of the adjoining property.
Finally, the court indicated that it would not have allowed the amendments in any event. The amendments were made late (only a few weeks before trial), the delay had not been explained and any amendment would have required Willmott Dixon to both reconsider its entire case, and adduce further expert and factual evidence. The amendments, if allowed, would have necessitated an adjournment to the trial.
This case will be welcomed by contractors and highlights that although there are exceptions to the general rule that a party is not liable for the torts of its sub-contractors, the circumstances where a contractor will be held responsible for procuring the careful performance of work delegated to others will be limited.
Even when there is a non-delegable duty a breach of duty must still be established. Further, in order to maintain a claim for contributory negligence, the acts or omissions relied upon must have caused damage to the party against whom contributory negligence is pleaded. Loss and damage suffered by a third party will not suffice.
It is respectfully suggested that the judge took a pragmatic and welcome approach to the RWC's application to amend. Willmott Dixon had been allowed to prepare its entire case on a fundamentally different basis. The proposed amendments would have required a drastic re-think of the evidence (both factual and expert) that would need to be relied upon in order to deal with the new issues raised, necessitating an adjournment. Courts may in future be reluctant to allow amendments which will threaten the trial date, notwithstanding the court's power to order that RWC pay the cost of the adjournment.