A two-partner firm of consulting engineers receives a notification in April that a tenant of a small commercial building they designed in 2021 has discovered cracking in a load-bearing wall and is alleging the steel beam specification was inadequate. In June, before the April matter has resolved, an unrelated client — a developer of three small mews houses the firm designed in 2022 — writes alleging the foundations on one of the houses were under-designed and contributing to differential settlement.
Two separate claims, two separate underlying projects, two separate clients. The firm carries £1m of Professional Indemnity cover. The first claim is reserved at £450,000. The second, on early assessment, looks like £350,000. Are both covered? The answer depends entirely on how the £1m limit is structured in the policy. If the policy is written on an each-and-every-claim basis, both claims are fully covered against separate £1m limits. If the policy is written on an aggregate basis, the two claims share a single £1m pot — and if a third claim were to come in before renewal, there might be nothing left.
This article explains the distinction between aggregate and each-and-every claim limits in UK Professional Indemnity policies, when each structure applies, why some professional bodies mandate one or the other, and how the choice affects your real-world protection. It is written for principals at UK professional firms — accountants, architects, engineers, surveyors, IT consultants, designers, management consultants — who want to make an informed decision at renewal rather than accept whatever language appears on the schedule by default.
For the broader picture of PI cover see our introductory guide to Professional Indemnity Insurance; the specific terminology is unpacked in our PI insurance glossary.
The two structures, in plain English
The "limit of indemnity" on a Professional Indemnity policy is the most the insurer will pay out under the policy. The structure of that limit — the way the limit is applied across claims and across the policy year — is where the aggregate-versus-each-and-every distinction lives.
Each-and-every claim (sometimes written "any one claim" or "per claim") means the limit applies separately to every notified claim. If your limit is £1m on an each-and-every-claim basis, the insurer will pay up to £1m on the first claim, up to £1m on the second claim, up to £1m on the third claim, and so on, with no overall ceiling across the policy year. This is the broader of the two structures.
Aggregate means the limit is the total the insurer will pay across all claims notified during the policy year. If your limit is £1m in the aggregate and you have two claims totalling £900,000 in settlements, only £100,000 of cover remains for any further claim notified during the same year. The limit is depleted as claims are paid.
In practice, many UK PI policies use a hybrid structure. Common forms include:
- £1m each-and-every claim, no aggregate — the broadest. Each claim is met against a fresh £1m limit.
- £1m each-and-every claim with a £2m aggregate — each individual claim has £1m available, but the total payable across the year cannot exceed £2m.
- £1m in the aggregate — a single £1m pot for the year, shared across all claims.
- £1m each-and-every claim with aggregate for certain risks only — for example, the headline limit is each-and-every, but specific extensions (cyber, dishonesty, defamation) are sub-limited and aggregated.
The wording on the policy schedule is what controls. A schedule that simply says "Limit of Indemnity: £1,000,000" is ambiguous, and the underlying policy wording must be read to determine the structure. A schedule that says "Limit of Indemnity: £1,000,000 any one claim and in the aggregate" is unambiguous — it is an aggregate policy.
Why the distinction exists
The aggregate structure originated in the way insurers manage their own exposure. An each-and-every-claim policy with unlimited aggregate exposes the insurer to potentially unlimited losses in a single policy year if multiple unrelated claims arise. The aggregate cap is the insurer's mechanism for limiting that exposure.
From the policyholder's perspective the position is reversed. The each-and-every structure provides the broader cover — every claim is met against a fresh limit — and is more protective. The aggregate structure is narrower and exposes the policyholder to the risk of a year in which several claims exhaust the cover.
The market accommodates both, with each-and-every typically priced at a premium to aggregate cover of equivalent headline limit. The price differential varies by sector, claim severity expectations, and the insurer's appetite, but in 2025-26 the each-and-every premium uplift over an equivalent aggregate policy is often in the range of 15% to 35% for the same headline figure.
Which structure applies to your sector
Different UK professional bodies take different positions on whether their members must hold each-and-every or aggregate cover. Knowing what your regulator expects is the starting point.
Solicitors (SRA-regulated). The SRA Minimum Terms and Conditions require cover on an "any one claim" basis. The mandatory MTC limit is £2m for partnerships and unincorporated practices, and £3m for incorporated practices (LLPs and limited companies), each on an each-and-every-claim basis. There is no aggregate cap on the mandatory tier — every claim is met against a fresh limit. Cover bought above the mandatory minimum (top-up cover) can be on different terms; many firms buy excess layer cover on an aggregate basis for cost reasons because the deeper layer is less likely to be hit twice in one year.
Architects (ARB-registered). ARB's PII criteria explicitly require cover on an each-and-every-claim basis with no aggregate cap on the headline limit. The fee-income bands run £250,000 / £500,000 / £1m at the lowest, middle and upper bands respectively. ARB has been clear in published guidance that an aggregate-only structure does not meet its criteria for the main cover, though it acknowledges that some specific extensions (notably fire safety and cladding-related cover) may carry aggregate sub-limits.
Accountants (ICAEW). The ICAEW Professional Indemnity Insurance Regulations require cover that is "any one claim and in the aggregate" — explicitly an aggregate structure, with the minimum limit (£2m for the main tier) applying both per claim and in total across the year. This is a narrower mandatory floor than the architects' or solicitors' regime; ICAEW takes the view that aggregating cover is acceptable because most accountancy practices have a low frequency of claims.
Accountants (ACCA). ACCA's requirements use the language of "any one claim and in the aggregate" similarly to ICAEW, but with different fee-income scaling.
Surveyors (RICS). The RICS Minimum Approved Policy Wording requires "any one claim" cover on the main limit; RICS-regulated firms must hold each-and-every cover at their applicable turnover-band minimum (£1m at the upper band).
Insurance brokers and financial advisers (FCA-regulated). The FCA Handbook (IPRU-INV 13 and MIPRU 3 depending on activity) sets out PI minima for FCA-authorised firms, with the structure varying by activity. Most FCA mandatory limits are expressed as "any one claim" minima with aggregate cap permitted at a multiple.
Engineers (Engineering Council institutions). The Engineering Council does not centrally mandate PI for chartered engineers. ICE, IStructE and similar bodies treat PI as an expectation rather than a rule. In practice most engineering consultancies carry each-and-every cover because clients (particularly public sector and construction-industry clients) specify it contractually.
Unregulated professional activities — IT consultancy, management consultancy, design agencies, training providers, marketing consultancies, project managers, and so on. There is no central regulator mandating one structure. The choice is between policyholder, broker and insurer. The default in the UK market for unregulated professional activities has historically tilted toward aggregate cover because it is cheaper; many policyholders are unaware of the distinction.
A worked example: where the difference actually bites
A small architects' practice carries £1m of PI cover. Three matters arise during the policy year:
- April: A residential client alleges a defective extension design caused damp ingress. Insurer reserves the claim at £180,000.
- September: A commercial client alleges the practice's contract administration on a small office fit-out failed to detect cost overruns and unauthorised variations. Insurer reserves at £420,000.
- February (the following year, before renewal): A third client alleges design errors on a school remodel produced acoustic problems requiring £350,000 of remedial work.
Three claims, three unrelated underlying projects, three settled or reserved amounts totalling £950,000 over the policy year.
If the policy is each-and-every claim with no aggregate (the ARB-compliant structure): all three claims are fully covered. Each is met against a fresh £1m limit. The practice's only out-of-pocket cost is the excess on each claim, typically £2,500 to £10,000 each.
If the policy is £1m in the aggregate: the first two claims (£180,000 plus £420,000 = £600,000) deplete the limit, leaving £400,000 available. The third claim at £350,000 sits within the remaining limit but only just; if it had been £450,000, the practice would have been personally exposed for £50,000. And if a fourth claim had arrived before renewal, the policy would have been exhausted.
If the policy is £1m each-and-every claim with a £2m aggregate: all three claims fit within the £2m aggregate ceiling, so all three are fully covered. The aggregate cap is comfortable; the structure is meaningfully broader than the £1m aggregate but cheaper than the unlimited-aggregate each-and-every policy.
The example is not a worst case. It is a normal-shaped year for a mid-sized architectural practice. The aggregate-versus-each-and-every choice is what determines whether that normal year results in full cover or in a personally-exposed shortfall.
When aggregate cover is actually fine
It is easy to read the comparison above and conclude that each-and-every cover is always the right answer. That is not quite right. Aggregate cover is genuinely appropriate in three situations.
The first is where the regulator mandates it as the baseline — ICAEW accountants carrying aggregate cover are following the rulebook, and that is the structure their professional body has determined is appropriate. The case for buying broader cover above that baseline is real but is a separate question from regulatory compliance.
The second is where the firm's claim frequency is genuinely very low — practices that have not had a single notification in five years, that operate in low-claim sectors, and that have small client books. For such a firm, the probability of multiple claims in a single year is low enough that an aggregate cap is not a meaningful exposure, and the premium saving funds higher headline cover.
The third is on excess layer cover. Many firms with serious PI exposure buy a primary policy on each-and-every terms and a higher excess layer on aggregate terms. The logic is that the excess layer only responds if the primary is exhausted, and the probability of two independent multi-million-pound claims in the same year is low enough to make aggregate cover at that level acceptable. The cost saving on the excess layer is often substantial.
The aggregate trap: an underwriting structure you may not realise you have
A specific issue worth flagging: some policies described to the policyholder as "£1m of cover" turn out, when the wording is read carefully, to be £1m in the aggregate rather than each-and-every. This is most common in policies sold to unregulated professional activities through online distribution channels or smaller intermediaries where the policyholder is not given a full talk-through of the structure.
The schedule may carry language like "Limit of indemnity: £1,000,000 any one claim and in the aggregate" — which means the £1m is both the per-claim limit and the annual cap. A policyholder reading "any one claim" naturally assumes there is no aggregate cap, but the addition of "and in the aggregate" reverses that.
The practical check: ask the broker to confirm in writing whether your policy is each-and-every with unlimited aggregate, each-and-every with a stated aggregate (and what that aggregate is), or aggregate-only. The answer should appear in the policy wording or in the schedule. If it does not, the wording controls and you need to read it.
This is one of the items on our renewal checklist piece, PI insurance renewal — what to check before you sign.
Defence costs — in addition to, or eroding, the limit
Closely related to the aggregate-versus-each-and-every question is how defence costs are treated against the limit. UK PI wordings vary on this and the variation matters.
Costs in addition (sometimes "defence costs in addition" or "100% costs inclusive"): the insurer pays defence costs in addition to the limit of indemnity. A £1m limit with costs in addition could in principle see the insurer pay out the full £1m to the claimant plus an extra £200,000 in legal fees. This is the most protective structure for the policyholder.
Costs inclusive (sometimes "costs within the limit" or "costs eroding"): defence costs are paid from within the limit. A £1m limit with costs inclusive that incurs £200,000 of defence costs leaves £800,000 available to settle the claim itself.
The SRA Minimum Terms and Conditions for solicitors require costs in addition for the mandatory tier. ARB does not mandate either approach explicitly but the market default for architects' MTC-compliant cover is costs in addition. ICAEW's regulations require costs in addition (or "100% indemnity") for the qualifying insurance. For unregulated professionals the default has historically been more variable.
Where defence costs are within the limit and the claim is contested heavily, defence costs alone can consume 20% to 40% of the limit before any settlement is paid. On an aggregate policy this compounds — the limit is being eroded by both settlements and defence costs simultaneously.
What to ask your broker before renewal
Three direct questions clarify almost everything about your policy's limit structure:
First: "Is my limit each-and-every claim, aggregate, or each-and-every with a stated aggregate? Show me the exact wording on the schedule." The answer should be in writing and unambiguous.
Second: "Are defence costs in addition to the limit, or within the limit? Confirm in writing." This is a separate question and equally important.
Third: "Which extensions on my policy are sub-limited or aggregated separately?" Common ones to ask about include fire safety / cladding (often aggregated and sub-limited), dishonesty of employees (sometimes sub-limited), defamation cover, contract works extension, and cyber-related extensions.
The answers to those three questions tell you what your policy actually does in a multi-claim year. If your broker cannot answer them quickly with reference to the wording, that is itself useful information about the relationship.
Stepping up cover — the practical options
If reading the above suggests your current structure is too narrow, the options at renewal are:
- Increase the headline limit while keeping the existing structure. If you have £1m each-and-every with a £2m aggregate, stepping to £2m each-and-every with a £4m aggregate is one option.
- Move from aggregate to each-and-every at the same headline limit. This widens cover at marginal premium cost; the broker should be able to quote the differential.
- Add an excess layer on top of your existing policy. Particularly cost-effective if your underlying limit is low — £1m primary plus £2m excess gives £3m total cover and is often cheaper than a £3m primary policy.
- Tighten the aggregate without changing each-and-every. For example, if you have £1m each-and-every with a £2m aggregate but want £3m of certainty, ask what £1m each-and-every with a £3m aggregate would cost.
The right answer depends on your sector's typical claim severity, your engagement values, your claims history and your premium budget. A broker who knows your sector should be able to talk through the options at renewal in concrete numbers.
Common mistakes and how to avoid them
Three patterns recur often enough to be worth flagging.
Assuming "any one claim" means "no aggregate". It does not. "Any one claim" describes the per-claim limit. A policy can be "any one claim and in the aggregate", which is an aggregate policy. The "in the aggregate" qualifier is what matters.
Buying the cheapest quote without reading the structure. Premium differences between brokers' quotes at the same nominal limit usually reflect underlying structural differences — aggregate versus each-and-every, costs inside or outside the limit, breadth of extensions, sub-limits on key risks. The cheapest quote is often the narrowest cover.
Treating the headline limit as the only thing that matters. Two policies at "£1m" can offer materially different protection. The structure matters as much as the headline figure, and a £1m each-and-every with costs in addition is genuinely more protective than a £1.5m aggregate with costs inside.
For broader renewal-time discipline, see our companion piece PI insurance renewal — what to check before you sign.
How Apex helps
Apex Insurance Brokers is an independent FCA-authorised broker. We are not tied to any one insurer and we act for the policyholder under FCA Conduct of Business rules. At renewal we will set out the structure of your existing cover, identify whether the limit and the aggregate position match your sector's expectations, and present alternative structures from the market for you to consider in concrete terms. The remuneration disclosure is on our Terms of Business page.
If you would like a second opinion on your existing policy structure — particularly if you have been with the same insurer for several years without a substantive review — contact us. We are based in Bristol and serve professional firms across the UK; the first conversation costs nothing and does not commit you to anything.
Frequently asked questions
What does "any one claim" mean on a PI policy?
"Any one claim" describes the per-claim limit — the maximum the insurer will pay on a single notified claim. A policy with a limit of £1m "any one claim" pays up to £1m on each claim. The phrase does not, by itself, tell you whether there is also an aggregate cap on the annual total. A policy can be "£1m any one claim with no aggregate" (the broadest), "£1m any one claim with a £2m aggregate", or "£1m any one claim and in the aggregate" (where £1m is both the per-claim and the annual cap). Read the schedule's full wording to know which structure you have.
Are aggregate limits allowed under UK regulatory minimums?
It varies by profession. The SRA Minimum Terms for solicitors require each-and-every cover with no aggregate cap on the mandatory tier. The ARB criteria for architects also require each-and-every cover. The RICS Minimum Approved Policy Wording for surveyors requires "any one claim" cover on the main limit. By contrast, ICAEW's regulations for accountants explicitly use "any one claim and in the aggregate", and ACCA's requirements similarly. FCA-regulated activities vary depending on the activity. Check your professional body's PI rules to see what is mandatory.
Why is each-and-every cover more expensive than aggregate cover?
Each-and-every cover exposes the insurer to higher potential payouts in a single policy year — every claim is met against a fresh limit with no annual ceiling. Insurers price that broader exposure. The premium uplift for each-and-every over an equivalent aggregate policy at the same headline limit is often in the range of 15% to 35%, depending on sector and the insurer's appetite. The broader cover is more expensive but is also more protective in a year with multiple notifications.
Can I have each-and-every cover on the primary and aggregate on the excess layer?
Yes, this is a common structure for firms carrying total cover of £3m or more. The primary layer (often the first £1m or £2m) is bought each-and-every for breadth, and the excess layer above is bought aggregate because the probability of a single year exhausting the primary on multiple independent claims is low enough that aggregate excess cover is accepted as cost-effective. Brokers structuring multi-layer cover should set this out explicitly in the placement.
What does "costs in addition" mean?
Defence costs in addition (sometimes "100% costs inclusive") means the insurer pays legal defence costs on top of the limit of indemnity. The £1m limit is available in full to settle the claim itself; the defence costs are a separate insurer expense. The alternative — "costs inside the limit" or "costs eroding" — means defence costs are paid from within the limit and reduce what is available for settlement. The SRA Minimum Terms require costs in addition; ICAEW's regulations require 100% indemnity cover (effectively costs in addition); ARB and RICS market practice strongly favours costs in addition.
Does the aggregate limit reset on renewal?
Yes. Each policy year has its own aggregate limit. A policy with a £2m aggregate that is exhausted in policy year one resets to £2m at renewal for policy year two — assuming the renewed policy is on the same terms. However, exhausting the aggregate during a policy year does not retrospectively reduce cover on claims already in train; once a claim is notified and the insurer is on risk for it, that claim continues to be handled even if the aggregate has been used up by other claims.
How do sub-limits interact with the headline limit?
Many PI policies carry sub-limits on specific extensions — fire safety / cladding cover, dishonesty of employees, defamation, loss of documents, cyber-related elements. A sub-limit is a smaller cap inside the main limit. A £2m main limit with a £250,000 sub-limit on fire safety means that fire-safety-related claims are capped at £250,000, even though the main limit is £2m. Sub-limits are commonly aggregated even when the main limit is each-and-every. The schedule should set them out clearly.
What is "one occurrence" or "single claim" aggregation?
Some wordings deem claims arising from a common cause to be a single claim for limit purposes. If two separate clients sue the same architect over the same defective design template, the wording may aggregate those into a single claim — relevant for the per-claim limit. This is generally protective of the insurer rather than the policyholder, and the aggregation language varies materially between wordings. Where multiple-related-claims is a foreseeable risk (template-based services, repeated-engagement work for the same client group), the aggregation language in the wording is worth reading carefully.
Related guides
- What is Professional Indemnity Insurance? UK Guide 2026
- PI insurance renewal — what to check before you sign
- PI insurance glossary
- Professional Indemnity insurance broker in Bristol
About Apex Insurance Brokers — Apex Insurance Brokers Limited is authorised and regulated by the Financial Conduct Authority, FCA firm reference 724952. Registered in England and Wales, Companies House 07014570. Last reviewed: May 2026.
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