The underlying dispute in URS Corporation Ltd v. BDW Trading Ltd [2025] UKSC 21 may have been prompted by recent changes to building safety standards, but the impact of this Supreme Court decision will be felt much wider. The judgment addresses several fundamental points of law that will be relevant to a wide range of disputes.

Factual background

The case concerned two high-rise residential buildings developed by BDW. In each case, BDW had appointed URS to provide structural design services.

In 2019, despite no longer having any proprietary interests in the blocks, BDW undertook post-Grenfell investigations and discovered that both blocks had design defects giving rise to serious safety risks. In 2020/21, BDW undertook works to remediate the defects even though, at the time, any claim by the homeowners for repair costs pursuant to the Defective Premises Act 1972 (DPA) would have been time-barred.

BDW brought a claim in negligence against URS based on its alleged failure to exercise reasonable skill and care in its design services.

On 28 June 2022, section 135 of the Building Safety Act 2022 (section 135) came into force, retrospectively extending the limitation period for accrued claims under section 1 of the DPA from six years to 30 years.

Subsequently, BDW obtained permission to amend its claim to include additional claims against URS under the DPA and the Civil Liability (Contribution) Act 1978 (CA).

Following various hearings, four key issues were referred on appeal to the Supreme Court.

Ground 1: in negligence, are voluntary losses irrecoverable as a matter of law?¹

URS argued that case law established a "voluntariness principle", namely that losses incurred voluntarily were outside the scope of duty and/or were too remote to be recoverable in a negligence claim. Given that, at the time BDW undertook the remedial works it had no proprietary interest in the blocks and there was (disregarding section 135 of the BSA) no enforceable legal obligation on BDW to undertake those works, the associated losses were voluntarily incurred and therefore irrecoverable.

The Supreme Court disagreed. Case law does not establish a principle of voluntariness.²

Instead, the issue of voluntariness is something that falls to be considered within the concepts of legal causation and mitigation, rather than scope of duty and remoteness. It is a fact-specific enquiry whether the chain of causation between breach of duty and loss has been broken – does the claimant's intervening actions break that chain of causation? With mitigation, the enquiry focuses on whether the steps taken were reasonable – were the expenses incurred that increased the loss reasonably incurred? "[I]n respect of neither concept can it be said that voluntariness constitutes a rule of law to the effect that there has been no legal causation or there has been a failure to mitigate".

While both issues (causation and mitigation) in this case will have to be determined at trial, the majority of the Supreme Court identified three factors suggesting that BDW was not, in a true sense, acting voluntarily when it incurred the cost of the remedial works:

• If BDW had done nothing and the defects had resulted in death or personal injury, any claim under the DPA or pursuant to the collateral warranties would not have been time-barred.
• BDW did have a liability under the DPA and via collateral warranties to the homeowners to incur the costs of repair. While that liability was (disregarding section 135 of the BSA) time-barred, "limitation bars the remedy and does not extinguish the right".
• There was reputational and moral pressure on BDW that made it in its commercial interest to undertake the repairs.

Lord Leggatt, giving a separate but concurring judgment, was of the view that:

• Lack of enforceable legal liability to remedy the defects was not conclusive evidence that BDW's actions were voluntary.
• While the High Court had held that reputational damages were irrecoverable, this did not preclude consideration of reputational consequences when judging the reasonableness of BDW's actions for the purposes of causation and mitigation.

Comment: While it makes sense that a party should not be able to voluntarily increase its losses and expect to recover them via legal action, reality is never going to be that straightforward. This is reflected in the Supreme Court's decision on this point which views voluntariness not as a standalone concept or legal rule, but as part of the complex factual matrix that will need to be considered when assessing two of the key legal components of a successful negligence claim, namely causation and mitigation – a clarification that will be relevant in other actions for negligence.

The Supreme Court's identification of factors indicating that the actions of BDW were not voluntary in the true sense demonstrate that the courts are likely to take a broad view when assessing the causal link between breach of duty and loss. This should be taken by those with ultimate responsibility as a warning to engage and respond to claims early, as otherwise they may lose the ability to shape any remedial action for which they are liable.

Ground 2: what is the extent of the retrospectivity of section 135?

At the time it undertook the remedial works, claims for repair costs against BDW pursuant to section 1 of the DPA were time-barred. However, following section 135, the legal position was changed retrospectively so that, at the time the works were undertaken, such claims would not have been time-barred.

The issue was whether BDW, in its claims for negligence and contribution (rather than any claim pursuant to the DPA), could now assert, based on section 135, that at the time it undertook the remedial works it was under an enforceable obligation to the homeowners for the costs of repair pursuant to section 1 of the DPA. If so, this would undermine any argument by URS that BDW's actions were voluntary and so would be relevant to issues of causation and mitigation that would have to be assessed by the trial judge.

URS argued section 135 applied only to a claimant bringing an action under section 1 of the DPA and a defendant asserting a limitation defence.

The Supreme Court held there was no basis to restrict the meaning or effect of section 135 to only direct claims brought pursuant to section 1 of the DPA. Such a construction would lead to contradictory results – for example, a homeowner would be able to bring a claim against a developer or contractor (or both) pursuant to section 1 of the DPA under the extended limitation period but neither the developer nor the contractor, if held liable in damages, could recover a contribution from the other. It would also undermine "the central purpose and policy" of the Building Safety Act 2022, which is to hold those responsible for building safety defects accountable.

Instead, it was held that the retrospective extension of the limitation period for claims pursuant to section 1 of the DPA extends to claims which are dependent on that section but are not brought under it. This changes the legal landscape retrospectively so that, at the time BDW undertook the remedial works, claims pursuant to section 1 of the DPA were legally enforceable. However, what it does not change is the factual landscape and the reasonableness or not of BDW's actions in carrying out the works as a matter of legal causation or mitigation.

Comment: Query the extent to which this will be played out in other claims and whether there is any scope for transposing the logic behind the interpretation of section 135 to other retrospective provisions. In particular, it will be interesting to see whether this decision has any bearing on how the Court of Appeal deals with the question of retrospectivity in the cases of Adriatic Land 5 Ltd v. Long Leaseholders at Hippersley Point and Stratford Village Development Partnership v. Triathlon Homes LLP – both appeals were heard earlier this year and judgment is awaited.

Ground 3: are developers owed duties under section 1 of the DPA?

Section 1(1) of the DPA states:

"A person taking on work for or in connection with the provision of a dwelling (whether the dwelling is provided by the conversion or enlargement of a building) owes a duty:

1. if the dwelling is provided to the order of any person, to that person; and
2. without prejudice to (a) above, to every person who acquires an interest (whether legal or equitable) in the dwelling,

to see that the work which he takes on is done in a workmanlike manner or, as the case may be, professional manner, with proper materials and so that as regards that work the dwelling will be fit for habitation when completed."

It was clear that BDW owed this statutory duty to the homeowners of the blocks. The issue was whether BDW could also be owed this duty by URS who had taken on the work because the dwellings in the blocks were provided "to the order" of BDW.

URS contended that BDW could not benefit from the duty. The purpose of the legislation was to protect consumers. Developers could manage risk and obligations through their contractual arrangements. It would also be anomalous and illogical for the DPA duty to be owed by and to BDW – the persons who owe the statutory duty and the persons to whom the duty is owed are mutually exclusive.

The Supreme Court disagreed and held that section 1(1)(a) of the DPA should be interpreted as applying to any person, including a developer, to whose "order" a dwelling is being built. Here, as the work URS was doing was carried out pursuant to the order of BDW, URS owed a section 1 duty to BDW.

Comment: The Supreme Court came to the same conclusion on this point as the Court of Appeal. By determining that developers (and others) can benefit from the statutory duty, the Supreme Court has given a wide interpretation of the scope of the statutory duty in section 1 of the DPA, moving away from any previous notion that the section was exclusively consumer-focused. It does, however, give rise to some issues for those in the construction industry as the statutory duty cannot be excluded by contract and so may cut across contractual allocation of risk.

Ground 4: the circumstances in which a cause of action accrues under the CA

The CA makes provision for situations where two parties are liable for the same damage. If a claimant claims against one or both parties, the parties can subsequently seek a contribution from each other according to the extent of their relative liability for the damage in question.

The issue here was whether BDW was entitled to bring a claim for contribution against URS pursuant to section 1 of the CA, despite there having been no judgment or settlement between BDW and any third party and no third party having ever asserted a claim against BDW.

URS argued that the right to recover a contribution did not arise unless one party had made or agreed to make a payment to the claimant in compensation for the damage and the existence and amount of that party's liability had been ascertained by judgment, an admission or a settlement which in turn implicitly requires a claimant to have asserted a claim.

The Supreme Court concluded that BDW was not prevented from bringing a claim for contribution against URS by the fact there had been no judgment against BDW or settlement between BDW and any third party, and no third party had ever asserted a claim against BDW. Instead, it was enough that BDW had made a payment in kind by doing the remedial works in compensation for the damage suffered by the homeowners in the blocks.

Comment: This part of the decision significantly broadens the understanding of when contribution claims can be brought pursuant to the CA. This decision encourages proactive remediation of safety risks by confirming that parties can seek contribution from other liable parties without waiting for an actual claim or legal threat. The ruling provides reassurance to those who take responsible action early, knowing they can still pursue fair cost distribution among all liable parties.

Concluding thoughts

One uniting thread throughout the Supreme Court's decision was consideration of the underlying objectives. Recent building safety changes have been driven by two key policy aims: first, to encourage parties to take responsibility for defects in buildings that raise safety concerns; and second, to ensure that the cost of remedial works for safety defects falls on those responsible. The decision promotes these objectives while providing helpful clarification on several wider legal points.

1. There was an ancillary issue as to whether BDW had an accrued action in negligence at the time it sold the blocks, but it was not fully argued and not necessary to decide. ↩
2. While Lord Leggatt did agree with URS that "there is a general principle of the common law that damages cannot be recovered for consequences of a choice freely made by the claimant", he did agree with the majority that voluntariness "is most obviously and normally relevant to issues of causation and mitigation". ↩