The Bolam test (Bolam v Friern Hospital Management Committee [1957] 1 WLR 582) governs the standard of care owed by professionals in negligence. The courts apply the same principle to consulting engineers — structural, civil, mechanical, electrical and geotechnical. The engineer is not judged by the standard of the most cautious practitioner, nor by hindsight. The question is whether the engineer acted in accordance with a practice accepted as proper by a responsible body of competent practitioners in the same field at the time.
That responsible body of opinion is identified by reference to published engineering practice — the Eurocodes (BS EN 1990 through BS EN 1999), pre-Eurocode British Standards still in use, and guidance from the Institution of Structural Engineers, the Institution of Civil Engineers, the Institution of Mechanical Engineers and the Institution of Engineering and Technology. Expert evidence from peers, weighed against that documentary record, is how the standard is established at trial.
Bolam sets the tortious baseline, but engineering retainers frequently impose a higher contractual standard. In Greaves & Co (Contractors) v Baynham Meikle & Partners [1975] 1 WLR 1095 the Court of Appeal held that consulting engineers who knew the warehouse floor was to carry fork-lift truck traffic had impliedly warranted that the design would be fit for that purpose — a strict obligation, independent of fault. In Independent Broadcasting Authority v EMI Electronics and BICC Construction (1980) 14 BLR 1 the House of Lords reached a comparable result for a television mast designed under a turnkey contract.
The position was confirmed in MT Hojgaard A/S v E.ON Climate & Renewables UK Robin Rigg East [2017] UKSC 59, where the Supreme Court held that a contract for offshore wind turbine foundations could impose a fitness-for-purpose obligation even where the engineer had complied with the specified international design code. Compliance with the code was not a defence where the contract independently required the foundations to have a 20-year service life.
An engineer under a design-and-build appointment, an EPC contract or a bespoke consultancy agreement may therefore face a stricter standard than Bolam. The PI policy response, and the engineer's ability to argue a responsible-body defence, turns on the contract wording as much as on the engineering.
Eurocodes and BS standards are persuasive evidence of competent practice, but they are not a complete answer. A code sets minimum requirements; it does not relieve the engineer of professional judgement where ground conditions, loading patterns or material behaviour fall outside the code's assumptions. Departing from a code is not negligent per se, but the engineer must justify the departure on engineering principles a responsible body would recognise.
For higher-risk buildings, the Building Safety Act 2022 and the associated regulations have added the principal designer role under the Building Regulations. An engineer accepting that role takes on coordination duties across the design team and a statutory duty to plan, manage and monitor the design work for compliance with the building regulations. Breach exposes the engineer to regulatory enforcement and to civil claims that sit alongside the common-law Bolam analysis. The standard remains reasonable skill and care, but the scope of the duty has widened.
Worked example — illustrative only. A consulting structural engineer designs steel connections for a long-span warehouse. Three years after completion, fatigue cracks appear at several welded joints. The owner brings a claim. Two structural experts disagree on whether the fatigue analysis under BS EN 1993-1-9 (Eurocode 3, fatigue) was adequate for the cyclic loading the structure actually experienced.
Under Bolam, if the defendant engineer can show that a responsible body of structural engineering practice — supported by the Eurocode 3 detail-category approach and IStructE guidance current at the time — would have carried out the analysis in the same way, the claim in negligence is likely to fail, even though the rival expert would have done it differently. If, however, the design contract included a fitness-for-purpose warranty for the intended service life and loading regime, breach is established by the fact of the fatigue failure, regardless of whether the analysis met the Bolam standard. The PI insurer's response will depend on whether the policy answers contractual liabilities assumed beyond the common-law duty.
Apex Insurance Brokers Limited is authorised and regulated by the Financial Conduct Authority. Firm reference number 724952. This entry is general information, not advice on any particular policy.