Building Design Partnership Ltd v Standard Life Assurance Ltd

Citation: EWCA Civ 1793

On Monday 29 November, the Court of Appeal gave judgment in Building Design Partnership Ltd v Standard Life Assurance Ltd on the viability of pleading a professional negligence claim on an extrapolated basis. Dismissing the appeal, the Court upheld the judge’s refusal to strike out (or grant reverse summary judgment on) the parts of Standard Life’s claim that were based on extrapolation. The Court held that, in an appropriate case and with proportionality in mind, extrapolation can be used to plead claims against a professional in relation to an unknown population of the professional’s work based on a known sample of the professional’s work.

The appeal raised a novel point as to whether breaches must be alleged to be systemic in order to support inferences of negligence against a professional.

BDP argued that sampling and extrapolation were only appropriate in cases of alleged systemic failure, where what was essentially the same defect arose across a project. In giving the leading judgment, Coulson LJ rejected that distinction; there was nothing special or different about a professional negligence action that prevented an extrapolated claim being pleaded as part of such a claim.

The Court also rejected BDP’s floodgates argument that allowing the pleading in this case to stand would encourage undetailed claims, stating that pleading every detail should not be regarded as the paradigm method of framing construction disputes, particularly where there are more proportionate alternatives that enable a defendant to know the case it has to meet. The details might have to be investigated in certain types of construction disputes, but that should only ever be commensurate with the overriding objective.

Jonathan Selby QC and Callum Monro Morrison acted for the Respondent, instructed by Mayer Brown International LLP.

Vincent Moran QC and William Webb acted for the Appellant, instructed by Vinson & Elkins RLLP.


Vincent Moran KC
Jonathan Selby KC
William Webb KC
Callum Monro Morrison

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