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Reviewed by Matthew Bartlett, Director · Last reviewed 2026-06-23
Professional indemnity (PI) and public liability (PL) are the two liability covers most professional services firms carry. They protect against fundamentally different risks and one is not a substitute for the other. This entry explains the practical difference, the overlap, and the situations where firms get tripped up — and, because the two policies respond to entirely different events, why a firm can be perfectly insured for one type of claim and completely exposed to the other.
Public liability insurance responds to third-party bodily injury or property damage caused by the insured's business activities or premises. A visitor slipping on a wet floor, an architect's site visit triggering damage to the contractor's plant, a consultant spilling coffee on a client's laptop — these are PL claims. The common thread is that something in the physical world was harmed: a person was hurt, or property belonging to someone else was damaged, as a by-product of how the business operates rather than the quality of its professional judgement.
Professional indemnity insurance responds to financial loss suffered by a client (or in some cases a third party) as a result of negligent professional advice, design, or services. An incorrect tax return causing the client to pay penalties, a structural calculation error causing remedial works, a financial recommendation causing investment loss — these are PI claims. Here nothing need be physically damaged at all. The loss is monetary, and it flows from the exercise (or failure) of professional skill: an opinion, a specification, a piece of work the client paid the firm to get right.
The two policies are also built differently. PI is almost always written on a claims-made basis, meaning the policy that responds is the one in force when the claim is first made against you (or a circumstance is notified), not the one in force when you did the work. PL is typically written on a claims-occurring basis, meaning the policy in force when the injury or damage happened is the one that responds, even if the claim surfaces years later. That structural difference is why lapsed or under-maintained PI cover is so dangerous for professionals — and why run-off cover matters when a firm closes or a partner retires.
Ask whether the loss is:
This works for most claims. The complications arise where a single event causes both types of loss, or where the categorisation depends on whether the harm was caused by professional advice or by physical activity. A useful second question is: what was the firm being paid to do? If it was being paid to think — to advise, design, calculate, certify or represent — a shortfall in that work points to PI. If the harm arose from simply being present, occupying premises, or carrying out a physical task, it points to PL.
A few claim scenarios sit on the boundary:
Because these boundary cases can generate arguments between insurers about which policy responds, the practical protection is to place PI and PL with structures that dovetail — ideally through one broker who can see both wordings. Where the two sit with different insurers on inconsistent terms, a firm can find each carrier pointing at the other while the claimant waits, and the gap between the two wordings becomes the firm's own exposure.
The distinction is easiest to feel through examples. Each of the following is a composite of the kind of matter that reaches a professional-firm broker.
Most professional services firms hold:
Many firms also add:
These are usually packaged as a "professionals' combined" policy that runs PI alongside PL, EL, contents, and cyber in a single contract. Packaging is not just administratively tidier — it reduces the risk of gaps at the seams, because one insurer (or one co-ordinated programme) is looking at the whole picture and the definitions of "professional services", "occurrence" and "damage" are more likely to align across the sections.
PI premiums are driven by:
PL premiums are driven by:
This matters because changes to the business affect the two covers differently. A consultancy that takes on more on-site project management work needs to think about PL even if its fee income is unchanged. A firm that moves entirely to remote working may see PL relax but PI unchanged. It also matters at renewal: because PI is rated largely on fee income and work type, growth or a shift into higher-risk services (for example, a design firm moving from fit-out into structural or fire-safety work) can move the PI premium sharply while barely touching PL — and the reverse is true for a firm that opens a second office.
Getting the amount of cover right is as important as choosing the right policy. The two covers are sized on different logic.
Professional indemnity is sized against the worst realistic financial loss a piece of your work could cause a client — not against your fee for the job. A modest fee can sit under a project worth many multiples of it, and the claim follows the loss, not the invoice. Firms should also check how the limit applies: an aggregate limit is the most the insurer will pay across all claims in the policy year, whereas an each-and-every-claim limit resets per claim. Where cover is aggregated, a firm exposed to several claims in one year can exhaust the limit, which is why defence-costs treatment (inside or in addition to the limit) and any reinstatement provision deserve a close read.
Public liability is sized against the largest injury or third-party property loss your operations could plausibly cause. For an office-based practice a lower limit may suffice; for a firm regularly on construction sites or working near expensive plant and services, higher limits are prudent, and main contractors frequently impose a contractual minimum before they will let a professional on site.
Two other factors commonly set the number for you. First, client and contract requirements: engagement letters, framework agreements and public-sector tenders routinely stipulate a minimum PI limit, and sometimes a PL limit. Second, regulatory minimums: several regulated professions have mandatory PI floors and specific policy terms, so the amount and the wording are partly fixed by the professional body rather than chosen freely.
| Cover | Typical minimum | Typical for medium firm |
|---|---|---|
| Professional indemnity | £1m | £2m – £10m |
| Public liability | £1m | £2m – £5m |
| Employer's liability | £5m (statutory) | £10m |
The right level depends on contract size, client requirements, and risk profile. Many client contracts now specify minimum PI levels and a few specify PL — read what is contractually required before sizing cover. Whatever limit you choose, remember that under the Insurance Act 2015 you owe a duty of fair presentation of the risk: disclosing your activities, income and claims history accurately at placement and renewal is what keeps the cover reliable when a claim actually lands.
No. Public liability responds to bodily injury and third-party property damage, not to financial loss caused by defective advice, design or services. If a client sues because your work was wrong rather than because someone was hurt or something was damaged, that is a professional indemnity matter. Relying on PL to cover professional error is one of the most common and costly misunderstandings.
You can, but for most professional firms it leaves a real gap. A purely advisory practice with no premises visitors and no site work might carry PI alone; a trade with no advisory element might carry PL alone. The moment a firm both advises clients and has people visiting premises or attending sites, both exposures are live and a professionals' combined policy usually makes sense.
It depends on the cause. If the loss stems from negligent professional work, PI responds; if it stems from physical injury or damage, PL responds; and a single incident can genuinely trigger both. Because insurers can dispute the boundary, placing PI and PL so their wordings dovetail — ideally through one broker — reduces the risk of a claim falling between them.
There is no single across-the-board legal requirement, but many regulated professions must hold PI to specified minimum terms as a condition of practising, and countless commercial contracts require it before work can begin. Employer's liability, by contrast, is required by law for virtually any UK business with employees, with a £5m statutory minimum.
Because PI is claims-made, cover ordinarily needs to remain in place after you finish the work — claims can arrive years later. When a firm closes, merges or a principal retires, run-off cover keeps a policy responding to claims about past work even though no new work is being done. Some professions set minimum run-off periods; it is a point worth planning for well before the last day of trading.
Apex Insurance Brokers Limited places PI and combined commercial cover for UK professional services firms. FCA firm reference number 724952. We are happy to discuss whether a standalone PI policy or a combined professionals' package is the right structure for a firm of your size and risk profile.
Apex Insurance Brokers serves UK professional services firms and commercial businesses. Call 0117 325 0027, email info@apexinsurancebrokers.co.uk, or request a quotation.
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