Aggregation under the SRA minimum terms: clause 2.5
The four limbs, and what each one actually does
Limb one — one act or omission. The narrowest. It captures a single discrete error that harms several people at once: one mistaken certificate relied on by multiple parties, one missed deadline that defeats several claims. It does not capture repetition. A course of conduct made up of many separate errors is many acts, not one, however consistent the motive behind them. We deal with that limb on its own at the same act or omission.
Limb two — one series of related acts or omissions. Wider, but not as wide as it reads. The authority here is Lloyds TSB General Insurance Holdings v Lloyds Bank Group Insurance Co Ltd [2003] UKHL 48, in which the House of Lords held that this kind of wording requires each claim to arise out of the series taken as a whole, rather than out of one member of it. That is a demanding test. A common cause, a common perpetrator or a common failing is not enough on its own if each claimant’s loss flows from their own transaction.
Limb three — the same act or omission in a series of related matters or transactions. This is the limb for the single repeated error: the identical defective clause dropped into every lease in a development, the same wrong assumption applied file after file. It requires both that the act or omission be the same and that the matters or transactions be related.
Limb four — similar acts or omissions in a series of related matters or transactions. The widest, and the one construed by the Supreme Court in AIG Europe Ltd v Woodman [2017] UKSC 18.
What AIG Europe v Woodman decided
The Supreme Court was asked what “a series of related matters or transactions” means in the fourth limb. It rejected the Court of Appeal’s gloss that the transactions had to share an “intrinsic relationship” with each other, describing that requirement as neither necessary nor satisfactory and the term itself as elusive. It also rejected the first instance formulation that the transactions had to be dependent on one another, which was too restrictive. What the word “related” requires is that the matters or transactions fit together in some way — a determination to be made on the facts, looking at the transactions objectively and in the round, and asking whether they are connected in significant ways.
On the facts, claims arising from each of the two developments could aggregate within that development, because the investors in each were co-beneficiaries under a common trust of the same security. Claims across the two developments could not be aggregated with one another merely because the two schemes were strikingly similar in structure. The case was remitted for the test to be applied to the facts.
The practical lesson is that limb four is a judgement, not a formula. The Supreme Court deliberately declined to reformulate the clause into a mechanical rule, which means both insured and insurer are arguing about degree and connection rather than applying a checklist — and both sides can be genuinely uncertain until the facts are laid out.
The one matter or transaction rule
The final part of clause 2.5 is easy to skim and important. All claims against one or more insured arising from one matter or transaction are regarded as one claim, regardless of how many claimants there are or how many separate acts contributed. A single conveyance that goes wrong in several ways, generating claims from buyer, lender and a third party, is one claim under the minimum terms. That is generally to the insured’s advantage where the limit is any-one-claim, because one full limit answers all of it and one excess applies.
Why this matters more to solicitors than to most
Because the wording is fixed, the negotiation moves elsewhere: to the limit, to the excess structure, and above all to how work is organised so that a systemic error cannot propagate unchecked. A firm doing a high volume of similar transactions on a common template is, by construction, building a limb three and limb four exposure. Understanding that before it crystallises is what allows the limit to be set sensibly and the excess arrangements to be checked. Our guide to the SRA minimum terms covers the rest of the mandatory wording, and the solicitors’ PI page sets out how the market is placed.
Two cautions. First, the minimum terms are a floor, not a ceiling: an insurer may offer wider terms, and excess layers above the compulsory primary limit are not required to follow the minimum terms at all, so aggregation can behave differently higher up a tower. Second, the wording is periodically reviewed, so check the current SRA text rather than relying on a copy in an old file.
Frequently asked questions
What are the four aggregation limbs in SRA clause 2.5?
Claims are regarded as one claim if they arise from one act or omission; one series of related acts or omissions; the same act or omission in a series of related matters or transactions; or similar acts or omissions in a series of related matters or transactions. The clause also provides that all claims arising from one matter or transaction are regarded as one claim.
What did AIG Europe v Woodman change?
It settled how the fourth limb’s phrase “a series of related matters or transactions” is read. The Supreme Court rejected both the Court of Appeal’s “intrinsic relationship” requirement and the first instance requirement that the transactions be dependent on each other. Related simply means the matters fit together, judged objectively on the facts and in the round, asking whether they are connected in significant ways.
Can a solicitors’ firm negotiate its aggregation wording?
Not on the compulsory primary layer. Clause 2.5 is prescribed by the SRA minimum terms and every participating insurer must offer at least those terms. What can be influenced is the limit, the excess arrangements, the terms of any excess layer above the compulsory primary limit — which need not follow the minimum terms — and how the firm organises work so a single error cannot repeat across a book.
Is aggregation under the minimum terms good news for a firm?
Often yes. Where the limit is expressed on an any-one-claim basis, treating many related claims as one claim means one full limit responds and one excess applies, rather than a separate excess per file. It becomes unhelpful where the aggregated claim is large enough to exhaust the limit and leave the firm exposed for the balance, which is why the aggregated scenario, not the single-file one, should set the limit.
This page is general insurance information about how aggregation provisions in UK professional indemnity policies are commonly drafted and argued. It is insurance information, not legal advice, and it is not a statement of what any particular policy covers. Position stated as at August 2026. Where a claim, a circumstance or a limit is actually in issue, read your own wording and take advice on your own facts.
Apex Insurance Brokers Limited is authorised and regulated by the Financial Conduct Authority (FRN 724952). This page is general information, not advice on a specific policy.