Business Interruption Insurance Explained

The fire at Dawn’s café in Sheffield started in a neighbouring unit at two in the morning. By lunchtime her insurer had confirmed the building and equipment were covered. She remembers feeling relieved — until the loss adjuster asked, gently, how she planned to pay herself, her two staff and the rent during the five months the refit would take. The building was insured. The silence wasn’t. That’s the exact gap business interruption insurance in the UK exists to fill, and it’s the policy small business owners most often discover they needed only after the worst has already happened. Here’s how it works, in plain English.

Business Interruption Insurance at a Glance

What it pays	The profit you’d have made, plus rent, bills and staff wages, while you can’t trade
What triggers it	An insured event — usually fire, flood, storm or theft damage to your premises
Indemnity period	12, 24 or 36 months of payments — 75% of policies choose only 12
The big trap	43% of policies are underinsured, by an average of 53% (CILA)
Typical cost	From around £7 a month; roughly 0.1–0.5% of annual turnover
How it’s sold	As an add-on to your property or contents insurance

The Gap in “Fully Insured”

Most owners think of insurance as protecting things: the building, the kit, the stock. Property insurance does that job well — it paid for Dawn’s new kitchen. What it doesn’t do is replace the £9,000 a month her café would have taken through the till while the builders were in. The rent didn’t pause. The loan repayments didn’t pause. Her best barista found another job in week three. It’s rarely the damage that kills a small business; it’s the months of zero income afterwards. Business interruption insurance exists to pay for that period — to put the business back in the financial position it would have been in if the fire had never happened. Our small business insurance guide shows where it sits in a typical policy stack.

What It Covers — and the Trigger Rule

A standard policy pays your lost gross profit, your ongoing fixed costs like rent and utilities, permanent staff wages, the cost of temporary premises, and the “increased cost of working” — sensible extra spending, like hiring equipment or paying overtime, that gets you trading again faster. The crucial rule to understand is the trigger: business interruption doesn’t stand alone. It only pays when the interruption is caused by an event insured elsewhere in your policy — typically physical damage from fire, flood, storm or break-in. A supplier going bust, a power cut with no damage, or a pandemic generally won’t trigger the standard wording — as thousands of businesses discovered in 2020. Digital disruption has its own product entirely — that’s cyber insurance, and the two make a logical pair.

The Jargon, Translated

Three terms do most of the damage in this corner of insurance, so let’s defuse them. “Gross profit” on an insurance form is not what your accountant means by it: insurers define it as turnover minus your variable, uninsured costs like stock and purchases — for most service businesses, that’s nearly all of your turnover, which surprises people. “Indemnity period” is how long the payments continue: twelve, twenty-four or thirty-six months, chosen by you when you buy. And “declaration-linked” means you declare an estimate of next year’s gross profit, the insurer adds an uplift — often a third — to allow for growth, and in return you avoid the harsh averaging rules. Get those three right and you’ve done 90% of the work of buying this policy well.

The 12-Month Trap

Here’s the mistake even well-insured businesses make. Around 75% of business interruption policies run for just a twelve-month indemnity period, and twelve months sounds generous — until you sequence a real disaster. Dawn’s fire took three weeks of insurance negotiation, eight weeks of drying and strip-out, then planning queries, then a builder’s schedule, then the refit, then re-hiring and retraining, then the slow months of winning back regulars who’d found somewhere else for their morning coffee. She reopened in month five and didn’t match her old takings until month eleven. A serious rebuild of commercial premises routinely takes longer than a year before a single customer returns. Choose your indemnity period against the worst realistic timeline, not the best one; the price difference between 12 and 24 months is usually modest, and it’s the cheapest part of the policy to get right.

The Underinsurance Trap

The Chartered Institute of Loss Adjusters has published a statistic every owner should know: 43% of business interruption policies are underinsured, by an average of 53%. Half the cover, roughly, that the business actually needed. It happens innocently — the accountant’s definition of gross profit instead of the insurer’s, turnover that has grown since the form was filled in, or a figure shaved to trim the premium. The consequences aren’t gentle. On a sum-insured policy, the “average clause” scales your payout down in proportion to the shortfall: insure half your real gross profit and even a small claim is paid at half. Declaration-linked policies are more forgiving, but only if the declaration was honest — 43% of those are under-declared too. This is the same family of problem we cover in what voids business insurance: the policy works exactly as well as the numbers you gave it.

What It Costs in 2026

For all its importance, this is not an expensive policy. Hiscox prices business interruption from £7.20 a month, small-business add-ons start around £50 to £80 a year, and a useful rule of thumb puts premiums at roughly 0.1% to 0.5% of annual turnover — a few hundred pounds for a typical café, salon or workshop. The price moves with your declared gross profit, the indemnity period, your trade, and your premises risk: a flood-zone unit or a commercial kitchen costs more than a first-floor office. It’s almost always sold as an add-on to property or contents cover rather than standalone, which is worth knowing when you compare packages. Whether you’re a limited company or a sole trader makes no difference to how it works — though if you’re running a business from home, check whether your home-business policy includes any interruption cover at all, because many don’t.

The Extensions Worth Asking About

The standard policy covers damage to your own premises, but your income can be interrupted by damage to places you don’t own, and that’s what extensions are for. “Denial of access” pays when you can’t reach your undamaged premises — a fire two doors down closes the street, a gas leak seals the block. Supplier and customer extensions cover damage at a key supplier’s or major customer’s site that stops your work. Utilities extensions cover failure of power, water or telecoms caused by damage at the utility’s end. Ask your broker to price the ones that match your dependencies — a bakery lives on its flour supplier and its power; a consultancy mostly doesn’t.

How to Buy It Right in Twenty Minutes

One evening with a calculator protects you from both traps. First, work out insurable gross profit the insurer’s way: last year’s turnover, minus only the costs that genuinely stop when you stop — stock, raw materials, outsourced work. Then add growth: what will that number be next year? Second, write a worst-case timeline: how long to be paid out, cleared, rebuilt, restocked, re-staffed and back to normal takings? Third, list your dependencies — the one supplier, the street access, the power supply — and price the matching extensions. Finally, diary a five-minute review each renewal, because last year’s figures underinsure this year’s business. Do that, and business interruption insurance becomes what it should be: the policy that means a fire costs you a bad year instead of the whole business — and one more reason to keep building the cash buffer that bridges the excess and the wait.

The Bottom Line

Dawn’s story is the good version: she’d taken business interruption cover with a 24-month indemnity period on her broker’s advice, the policy paid her rent, wages and lost profit for eleven months, and the café is busier now than before the fire. Business interruption insurance in the UK costs a few pounds a month, hangs off the property cover you probably already have, and fails only when the numbers fed into it are wrong. Check your gross profit figure, question the 12-month default, add the extensions your business genuinely depends on — and file it under the best boring decision you’ll make this year. Start with our complete guide to small business insurance to see the whole picture.

Frequently Asked Questions

What is business interruption insurance?

It’s cover that replaces your lost profit and pays ongoing costs — rent, bills, staff wages — while your business can’t trade after insured damage such as fire or flood.

How much does business interruption insurance cost in the UK?

From around £7 a month as an add-on to property cover. A common rule of thumb is 0.1% to 0.5% of annual turnover, depending on trade and indemnity period.

What is an indemnity period in business interruption insurance?

The length of time the policy keeps paying — usually 12, 24 or 36 months. Choose it against a worst-case rebuild and recovery timeline, not a hopeful one.

Why do business interruption claims get reduced?

Mostly underinsurance: 43% of policies are underinsured by an average of 53%, usually because the gross profit figure was calculated the accountant’s way instead of the insurer’s.

Is business interruption insurance worth it for a small business?

If your business depends on premises, equipment or stock, yes — the months of lost income after a fire or flood are usually a bigger threat than the damage itself.

Disclaimer: This article is general information, not financial advice. Policy wordings, triggers and extensions vary by insurer; figures quoted are 2026 industry data. Read your policy documents and speak to an FCA-authorised broker before buying or renewing cover.