ARB Code of Conduct and Practice: the PII requirement for UK architects

~5 min read

Reviewed by Matthew Bartlett, Director · Last reviewed 2026-07-06

Every architect registered with the Architects Registration Board in the United Kingdom must hold professional indemnity insurance that meets Standard 8 of the ARB Code of Conduct and Practice. The ARB is the statutory regulator of the profession under the Architects Act 1997, and Standard 8 sits alongside the other Standards in the Code (from Standard 1 on integrity to Standard 12 on complaints handling) as a mandatory requirement for continued registration. An architect practising without compliant PII is in breach of the Code and can face disciplinary sanction up to and including erasure from the Register. This entry sets out what Standard 8 requires, how it interacts with membership of the Royal Institute of British Architects, and the practical placement points that matter at renewal.

The statutory framework

The Architects Act 1997 established the ARB as the statutory regulator of the architectural profession in the UK and gave it the power to make a Code of Conduct binding on registered architects. The Code is periodically revised; the current version in force from 1 January 2023 restated Standard 8 in updated terms. Standard 8 requires an architect to hold "adequate and appropriate" insurance cover to protect the architect and clients against professional negligence claims, and requires the architect to be able to demonstrate cover on request. The ARB does not publish a prescribed wording; it operates an adequacy standard supported by the ARB's own guidance on what "adequate and appropriate" means in practice.

Who is bound

Every architect on the ARB Register carrying out architectural services — whether in private practice, as a partner or director in a practice, as a sole practitioner, or as an in-house architect where the client relationship attaches — is bound by Standard 8. Architects in employment where the employer's E&O cover attaches to their work may be able to point to the employer's policy for compliance, but they remain personally responsible for demonstrating cover. Architects who have retired from active practice but remain on the Register have a shorter compliance obligation but must still satisfy the ARB that adequate cover is in place if any residual work continues.

What "adequate and appropriate" means in practice

The ARB's guidance frames adequacy by reference to four factors. First, the nature of the work — a small residential practice carries a different exposure profile from a commercial practice signing off on £50 million schemes, and the limit should reflect the largest realistic loss on the current book. Second, the value of the work — the fee and, more importantly, the value of the project the architect is signing off on. Third, claims history — an architect with a paid claim or notified circumstance should size limit and wording accordingly. Fourth, the specific exposures of the work — architects certifying under building regulations, providing lead consultant services, or acting as contract administrator carry additional exposure that a design-only architect does not.

The consequence of the adequacy framework is that the ARB does not prescribe a minimum figure in the way the ICAEW prescribes 2.5× fee income or the RICS prescribes a turnover-band scale. Adequacy is judged case by case. In practice, insurers writing architects' PII operate to broadly similar minimums (typically £500,000 to £1 million for the smallest practices, scaling to £5 million or above for mid-market practices, and materially higher for practices doing high-value or high-rise residential work), and those insurer minimums operationally set the market floor rather than an ARB-imposed rule.

The RIBA layer

Membership of the Royal Institute of British Architects is voluntary and additional to ARB registration. RIBA members are bound by the RIBA Code of Professional Conduct, which has its own PII expectations. The RIBA Code broadly mirrors the ARB Code on PII but adds specific expectations around wording and documentation. Architects who are dual-registered (ARB + RIBA) must satisfy both codes; in practice, meeting the ARB requirement almost invariably satisfies the RIBA requirement, but the reverse is not guaranteed — RIBA membership does not by itself confer ARB compliance.

Where architects sit alongside other professions

Architects on integrated project teams may operate alongside RICS-regulated surveyors, engineers, and other consultants. Each professional's PII cover attaches to their own work, and the interaction can matter where a single instructing party seeks to recover against multiple consultants. The net contribution clause — discussed in its own entry on the net contribution clause and its PII implications — is a common contractual response to this multi-consultant exposure. Architects operating on integrated design-and-build projects should have the interaction reviewed at each engagement, not just at renewal.

BSA 2022 as the defining recent change

The single most significant recent change to the architects' PII landscape is the Building Safety Act 2022, particularly section 135's extension of the limitation period under section 1 of the Defective Premises Act 1972 to 30 years retrospectively and 15 years prospectively for defective residential dwellings. That change is the subject of its own entry on the BSA 2022 30-year limitation and architects. Every architect with material historical residential work is affected — the compliance framework itself did not change under BSA 2022, but the underlying claim exposure did, and adequacy under Standard 8 should be judged against the new limitation reality.

Worked example

Illustrative only. A three-partner architectural practice, £850,000 turnover, work profile: 55% residential, 35% commercial fit-out, 10% conservation and heritage. Two of the three partners are ARB-registered and RIBA members; the third is ARB-only. The practice signs off on RIBA Plan of Work Stage 4 designs and occasionally acts as contract administrator on domestic residential work. Broker recommendation given the residential BSA exposure, the contract administration role, and the mixed commercial book: £3 million primary layer with an explicit endorsement covering contract administration and building regulation certification, plus a £2 million top-up layer for a £5 million tower. Six-year run-off costed at binding as a planning number; 15-year run-off costed separately given the residential BSA exposure.