The Bolam test, derived from Bolam v Friern Hospital Management Committee [1957] 1 WLR 582, sets the benchmark for professional negligence across the regulated professions. An architect is not negligent if they have acted in accordance with a practice accepted as proper by a responsible body of architectural opinion. The test was framed for clinical negligence but the Court of Appeal and the Technology and Construction Court have consistently applied it to architects, engineers, and other ARB and Engineering Council-regulated professionals. For the broader doctrine and its civil and criminal application, see the entry on the Bolam test.
Unlike clinicians, architects rarely rely on a single textbook of accepted practice. The evidential base is layered: the ARB Code of Practice, RIBA guidance and Plan of Work, British Standards (notably the BS 8500 and BS 8000 series), the Approved Documents under the Building Regulations 2010, and CIRIA technical reports. A defendant architect typically discharges the Bolam standard by showing that a competent peer applying the same materials at the same date would have arrived at the same design choice.
Two early authorities shape how the courts apply this in design disputes. Worboys v Acme Investments Ltd [1969] 4 BLR 133 confirmed that an architect's duty in design is to exercise reasonable skill and care, not to guarantee a perfect outcome. George Wimpey & Co Ltd v DV Poole [1984] 2 Lloyd's Rep 499 sharpened the point: a designer who follows ordinary professional practice is not liable simply because a more cautious approach existed, provided the chosen approach was itself defensible.
The classic application. The claimant must prove that no responsible body of architects would have specified the detail in question. Disagreement between experts on what constitutes acceptable design is usually fatal to the claim, subject to the Bolitho gloss discussed below.
Where the retainer includes contract administration, the standard is what a reasonably competent architect would have inspected and recorded. Frequency, depth and documentation of site visits are measured against contemporaneous RIBA guidance.
Bolam applies to the accuracy of estimates and the management of change. A reasonable estimate that turns out to be wrong is not negligent if it was prepared on a basis a responsible body of architects would have used at the time.
Errors in planning advice or in interpreting Approved Document compliance are tested the same way. Approved Documents are evidence of accepted practice; they are not, on their own, conclusive of negligence either way.
Since Bolitho v City & Hackney Health Authority [1998] AC 232, the responsible body of opinion must also be capable of withstanding logical analysis. A court can reject a body of professional opinion that does not stand up to scrutiny, although in practice judges are slow to do so. For architects, Bolitho has gained renewed importance after Grenfell, where assumptions once treated as accepted practice are being re-examined.
An architect specifies an aluminium composite cladding system for a mid-rise residential block, completed in 2012. The system is later identified as combustible and replaced. The leaseholders' claim alleges design negligence. Two architectural experts give evidence. One says the specification fell outside accepted practice even at that date; the other says a responsible body of architects would have specified the same system in 2012, relying on the then-current BR 135 guidance and Approved Document B. Under Bolam alone, the second expert's evidence would ordinarily defeat the claim. Under Bolitho, the court may still ask whether the body of opinion the defendant relied on was logically defensible — particularly where contemporaneous fire-engineering literature flagged the risk. The outcome turns on the date of the design decision and the contemporaneous evidential record.
For Higher-Risk Buildings, the Building Safety Act 2022 and the associated competence framework (PAS 8671 for principal designers) raise the expected standard of evidence for what a competent designer should have done. Bolam still governs liability, but the responsible body of opinion is now measured against a documented competence regime. Designers operating in this regime should expect courts to scrutinise the competence trail more closely than they did before 2022.
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