An engagement letter is the single most important document in defining an accountant's exposure. It sets the scope of the work, identifies who may rely on it, and, increasingly, caps the firm's liability. Cases such as Manchester Building Society v Grant Thornton show that the purpose stated in the engagement shapes the scope of duty the courts will recognise, so a well-drafted letter is both a commercial and a defensive tool.
Accountants frequently limit their liability to a fixed sum or a multiple of fees. Such a cap is a contract term excluding or restricting liability for negligence, and under the Unfair Contract Terms Act 1977 it must satisfy the requirement of reasonableness in section 11. The court weighs factors including the relative bargaining positions of the parties, whether the client could have obtained the service elsewhere without the cap, and whether the cap bears a sensible relationship to the available insurance.
The Institute of Chartered Accountants in England and Wales permits liability limitation but requires that any cap be fair and reasonable and, in audit engagements, subject to the specific regime for liability limitation agreements under the Companies Act 2006. A cap set below a level a court would consider reasonable, or below the firm's regulatory minimum PI requirement, is unlikely to serve its purpose.
A liability cap and a PI limit are not the same thing, and they interact. A cap can reduce the firm's exposure on a given engagement, but only if it holds under the reasonableness test. Insurers will want to see that caps are used consistently and are defensible, because an unenforceable cap leaves the full claim in play. Apex helps firms think about how their engagement terms and their limit of indemnity fit together on the accountants PI guide.
The most valuable habit is consistency: the same clear scope, reliance and cap language on every engagement, reviewed as the work changes. A firm whose letters are current and internally consistent is easier to defend and easier to place. The same discipline governs the terms of business used by insurance brokers and other advisers.
A common source of unexpected exposure is work that grows beyond the original letter. A firm engaged for compliance accounts finds itself advising on a sale, a restructuring or a tax planning idea, and never updates the terms. When a dispute arises, the client points to the wider work actually done, and the carefully drafted scope in the original letter looks out of date. The remedy is to treat any material change in the work as a trigger to reissue or supplement the engagement terms, so that the documented scope keeps pace with reality.
A liability cap set sensibly should bear a rational relationship to the firm's PI limit and to the value of the work. A cap far below the available insurance may be attacked as an attempt to deprive the client of a remedy the firm could readily meet, while a cap above the firm's cover leaves an uninsured gap. Reviewing caps and the limit of indemnity together, rather than in isolation, is a discipline Apex encourages as part of a firm's annual renewal conversation.
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.