Professional Indemnity Insurance for New Expert witnesses — Your First Policy (2026)

Reviewed by Apex Insurance Brokers · Last reviewed 2026-08-05

1. Do you actually need PI as a new expert witness?

Let's be precise, because the honest answer has two halves.

There is no statutory regulator of expert witnesses, and no Act of Parliament that compels you to buy PI insurance. Unlike a solicitor or an accountant in public practice — whose regulators (the SRA, the ICAEW and others) mandate minimum PI terms — an expert witness is not licensed by a dedicated authority. So in the narrow legal sense, you can accept an instruction without a policy in place.

That is where the reassurance ends and the reality begins. In practice, three separate forces push almost every serious expert towards holding cover from day one:

Your instructing solicitors. Law firms increasingly ask an expert to confirm they carry PI before they will formally instruct. It protects their client, and it protects the firm's own position if your evidence is later challenged. Being able to answer "yes, I hold cover of £X" can be the difference between winning the instruction and losing it to someone who can.

The profession you already come from. Most experts are experienced practitioners in an underlying field — medicine, engineering, surveying, forensic accounting, construction, IT, and so on. If your primary profession has its own regulator or membership body, its rules may already require PI, and that requirement can extend to expert work you do in that field. A chartered surveyor giving evidence, for example, remains a chartered surveyor bound by their institution's standards. Check the rules of the body you belong to — they may settle the question for you before your instructing solicitor even asks.

Your own exposure. Even without an external duty, the financial reality is stark. If a court relies on your opinion and it turns out to be negligently wrong, the sums in dispute — and therefore any claim against you — can dwarf your fee for the report. PI insurance exists precisely to stand between a single mistake and your personal finances.

So: not legally compulsory, but in the world you're actually entering, close to essential from your first case.

2. When cover must start — from your first engagement

The instinct of many first-timers is to wait until they are "properly established" before arranging insurance. With PI, that instinct is exactly wrong, and understanding why will save you a great deal of worry later.

The moment you accept an instruction and begin forming an opinion, you have taken on the professional duty that PI is designed to cover. If your first report contains an error, the consequences of that error don't announce themselves on the day you write it. A dispute may run for a year or more; a challenge to your evidence might surface long after you've submitted it. The protection you need is protection that is already in force when the work is done and that continues to respond as time passes.

This is why day-one cover matters so much for an expert witness specifically. Your work has a long tail — a report written this month may not be tested until a hearing two years from now. Starting your policy at the same time as your first engagement means there is no gap in the record, and it starts the clock on something called your "retroactive date," which we'll come back to in section five.

Get a first-policy quote for your expert witness work →

3. How much cover a new practice needs

The headline figure on a PI policy is the limit of indemnity — the most the insurer will pay for a claim (or, depending on the policy, in total across the period). Choosing it is the decision new buyers agonise over most, so here is a clear way to think about it.

There is no single "correct" number. What drives the right limit for an expert witness is the size of the matters you give evidence in, not the size of your own fees. A £4,000 report in a multi-million-pound construction dispute carries far more potential exposure than the fee suggests, because the loss a negligent opinion could contribute to is measured by the value at stake in the case, not by what you charged.

Three practical anchors to weigh:

• Client-mandated limits. This is often the deciding factor. Some instructing firms, and some appointment terms, specify a minimum PI limit — commonly expressed as a round figure such as £1m, £2m or £5m. If a solicitor tells you they need to see a particular limit before instructing, that sets your floor.
• The value of the disputes you expect to work in. An expert in small-claims-scale matters sits at a very different level of exposure from one advising in high-value commercial litigation. Match the limit to the largest cases you realistically expect, not the average.
• Room to grow. As a new practice you can start proportionate to your first engagements and increase the limit as the value of your work rises. It's easy to revisit at renewal.

Limits such as £1m, £2m and £5m are common options to consider — they're illustrative starting points, not prices or recommendations. If you're unsure which fits, that's exactly the conversation to have with a broker before you buy, rather than guessing.

4. What shapes a first policy — what underwriters look at

Because you have no trading history, you might expect this to be the hard part. It's usually the opposite. An insurer pricing a new expert witness practice is assessing the nature of the risk far more than any track record, and there are only a handful of things they genuinely want to understand:

• Your estimated fee income. A reasonable projection of what you expect to earn from expert work in the coming year. An honest estimate is fine — nobody expects a new practice to have exact figures.
• Your qualifications and experience. This is where new experts are strong. Your years in your underlying profession, your credentials, and any relevant memberships all speak directly to the quality of your opinion — the very thing PI is concerned with.
• The type of work you'll do. The fields you'll give evidence in, whether your instructions come from claimants, defendants or single-joint-expert appointments, and the kinds of disputes involved.
• The limit of indemnity you want. As discussed above.

Notice what's not on that list: years of accounts, a claims history, or a long paper trail. A brand-new firm simply has less to provide, and a good insurer understands that. We won't quote a premium figure here — pricing depends on your specific answers, and anyone promising a number before seeing them isn't being straight with you. But the information gathering is genuinely light.

5. "Claims-made" — the one concept every first-timer should grasp

Almost all PI insurance is written on a claims-made basis. This is the single most important mechanical fact about your policy, and it's simpler than the jargon suggests.

Claims-made means the policy that responds to a claim is the one in force on the day the claim is made against you — not the policy that was in force when you did the work. So if you wrote a report in 2026 but a complaint about it lands in 2028, it's your 2028 policy that has to be live for you to be covered.

Two consequences follow, and both matter enormously for a new expert:

Continuity is everything. Because each year's policy covers the claims made that year — including claims about past work — you need to keep cover in place continuously, without gaps, for as long as your past reports could still generate a complaint. Let the policy lapse, and a claim about work you did while insured could fall into a hole with no policy to answer it.

The retroactive date. Your policy carries a "retroactive date" — usually the day your cover first started. Work done before that date generally isn't covered. This is precisely why starting your first policy at the same time as your first instruction is so valuable: it sets your retroactive date early, so that as the years pass, more and more of your back catalogue sits inside the protected window. Delay buying, and you leave your earliest — and often most exposed — work uninsured.

When you eventually stop practising, you can arrange what's known as "run-off" cover to keep protecting you against late claims about past reports. That's a conversation for the future, not your first policy — but it's worth knowing the option exists, because it's a direct product of how claims-made works.

6. How to buy your first policy

The process is more straightforward than most first-timers fear. In outline:

• Gather a little information. Your estimated fee income for the year, a short description of the expert work you'll do and the fields it covers, your qualifications and relevant memberships, and the limit of indemnity you're aiming for.
• Answer honestly. The proposal will ask whether you're aware of any circumstance that could give rise to a claim. As a new practice the answer is usually a clean "no" — but you have a duty to disclose anything you're genuinely aware of. Getting this right protects your ability to claim later.
• Choose your limit and check the terms. Confirm the limit meets any requirement your instructing firms have set, and look at the retroactive date and any excess.
• Put cover in force before your first report goes out. That's the whole point of everything above.

The reassuring part, worth repeating: a new firm has less to assemble than an established one. You're not chasing years of records — you're describing who you are and what you intend to do. If a question isn't clear, a broker can walk you through it rather than leaving you to guess. You can begin the proposal here and pause to ask questions at any point.

7. Common first-timer mistakes to avoid

• Waiting until you're "established." By the time a claim could arise, the work is already done. Cover needs to precede the risk, not follow your success.
• Sizing the limit to your fees. Your exposure tracks the value of the disputes you advise in, not what you invoice. Under-insure against the case, not the fee.
• Letting cover lapse between renewals. With claims-made policies a gap can leave past work stranded. Renew continuously.
• Assuming your day-job policy already covers you. Cover held through an employer or your main practice may not extend to independent expert witness instructions. Check — don't assume.
• Not disclosing known circumstances. A material fact left off the proposal can undermine a future claim. When in doubt, tell the insurer.
• Overlooking your professional body's rules. The requirements of the field you came from may already dictate your minimum cover. Read them before you buy.

8. About Apex — and why we can quote this fast

Apex Insurance Brokers Limited is an FCA-authorised insurance broker (FRN 724952), based in Bristol. We arrange professional indemnity cover for practitioners across a wide range of specialisms, including experts giving evidence in their field, and we're used to helping people who are buying their very first policy.

Because a new expert witness practice has a compact risk to describe, we can move quickly. Tell us your estimated fee income, the work you'll be doing and the limit you're after, and we can turn that into a quote without a mountain of paperwork. If you'd rather talk it through first — about limits, retroactive dates, or what your instructing solicitors will expect — a real person at Apex will take you through it in plain English.

Apex Insurance Brokers Limited is authorised and regulated by the Financial Conduct Authority (FRN 724952). This guide is general information, not advice on a specific policy.