Business Interruption Insurance UK Small Business Explained
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The Cover That Pays the Bills While You Cannot Trade
A fire closes your premises. Buildings and contents insurance repairs the damage. What pays the rent, the wages and the supplier invoices during the three months you are shut?
That gap is what business interruption insurance exists to fill, and it is one of the most misunderstood policies a small business buys. Owners assume they have it when they do not, and those who do have it often find at claim time that the sum insured or the indemnity period was wrong.
This explains how it works, where the traps are, and what to check on the policy you may already hold.
What It Actually Covers
The purpose is to put the business back in the financial position it would have been in had the loss not happened. In practice that means two things: the gross profit you lose while trading is disrupted, and the extra costs you incur trying to keep trading.
That second part is worth naming, because people forget it exists. Increased cost of working covers reasonable extra expenditure to limit the loss: renting temporary premises, hiring replacement equipment, paying for overtime or express delivery. Some policies also offer additional increased cost of working, which pays for measures that are worth doing even if they cost more than the income they save. Both are worth asking about.
The Property Damage Trigger
The single most important thing to understand: standard business interruption cover is tied to a property damage claim.
It responds when your business suffers physical loss or damage to property that is itself insured under your property policy. Premises floods, buildings policy pays, business interruption then covers the income lost during repairs. No property damage means no payout under a standard wording.
That is the design of the product, not small print, and it is why most businesses received nothing during the pandemic. Lockdown closed premises without damaging them.
What the Covid Test Case Settled
The Supreme Court judgment in the FCA’s test case, handed down in January 2021, found that policies containing specific non-damage extensions, particularly notifiable disease clauses and certain prevention of access wordings, did respond to pandemic losses. Policies with purely damage-based wording did not.
The lesson has outlived the pandemic. Wording matters here more than in any other class of business insurance, and two policies that look identical on a comparison site can behave completely differently at claim stage. Most insurers have since narrowed or excluded communicable disease cover, so if a non-damage extension appears in your schedule, read what it actually says rather than assuming it is broad.
Setting the Sum Insured
This is where small businesses lose money, and it happens in three separate ways.
Gross Profit, Not Turnover
Business interruption is insured on gross profit, not turnover. In insurance terms, gross profit is turnover minus the variable costs you would stop paying if you stopped trading, such as raw materials, bought-in stock and packaging.
Fixed costs continue whether you trade or not: rent, salaries, finance, utilities. Gross profit in this sense is the money you need to keep covering them.
A manufacturer turning over £500,000 with £200,000 of raw materials has an insurable gross profit of £300,000, not £500,000. Insuring turnover means paying for cover you cannot claim.
Not Your Accountant’s Gross Profit
The insurance definition and the accounting definition are different. Accounting gross profit often deducts costs that an insurer treats as fixed, such as wages, which produces a lower figure and leaves you underinsured.
Have your accountant and your broker agree the number together before the policy incepts. It takes one conversation and it is the difference between a full payout and a scaled-down one.
It Has to Cover the Whole Indemnity Period
The mistake that hurts most. If your indemnity period is 24 months, the sum insured must represent gross profit for 24 months, not one year. Insure a single year’s gross profit alongside a two-year indemnity period and you are underinsured by roughly half before anything has happened.
Build in expected growth across that period too, since the figure needs to reflect what the business would have earned, not what it earned last year.
Underinsurance and the Average Clause
If the sum insured is too low, most policies apply average: the insurer reduces the payout in proportion to the shortfall. Insure £150,000 when the correct figure was £300,000 and a £100,000 loss may produce £50,000.
This is the consequence of every mistake above, and it is why the arithmetic deserves an hour of proper attention.
The Declaration-Linked Alternative
Some insurers offer declaration-linked cover, where you declare an estimated gross profit and the policy provides an automatic uplift above it, commonly a third. In exchange you supply an annual declaration of actual figures. For a growing business it is a useful protection against accidental underinsurance, and it is worth asking whether it is available.
The Indemnity Period
The maximum length of time the policy will pay out after an insured loss, usually offered at 12, 24 or 36 months. It runs from the date of the damage, not from the date you reopen.
Choosing 12 months because it is cheapest is the commonest error in this class. Work through what actually happens after a serious fire:
- Loss adjusters assess, which takes weeks
- Planning permission may be needed, which takes months
- Rebuilding or refurbishment, months more
- Refit, equipment, staff, restocking
- Rebuilding the customer base, which frequently takes longer than the construction
A business on a 12-month period that takes 18 months to return to normal trading gets nothing for the last six. That gap kills otherwise viable businesses.
Most independent brokers treat 24 months as the minimum for a small business, and recommend 36 for specialist premises or where customer relationships take time to rebuild. The premium difference between 12 and 24 months is usually modest compared with the exposure.
Extensions Worth Asking About
These are rarely included as standard in SME package policies.
Denial of access. Responds when an authority prevents or restricts access to your premises, for example a police cordon after a fire next door, where your own property is undamaged.
Supplier failure, sometimes called contingent business interruption. Covers loss caused by damage at a supplier’s premises. Usually requires the supplier to be named, and matters most where one supplier dominates.
Customer failure. The mirror image, for businesses dependent on one or two large customers.
Utilities failure. Loss of income from failure of gas, electricity or water not caused by damage to your own property. Critical for restaurants, manufacturers and anyone with cold storage.
Loss of attraction. Responds where damage to a nearby property reduces footfall to yours, which is relevant for retail and hospitality in a shopping area or near a landmark.
Check What You Already Have
Many commercial combined and package policies include some business interruption cover automatically alongside buildings, contents and public liability. The defaults are the problem: a 12-month indemnity period and a sum insured from a generic calculation rather than your figures.
Pull out your schedule and check four things:
- The indemnity period
- How the sum insured was calculated, and whether it reflects gross profit over the full indemnity period
- The insuring clause, and whether it is purely damage-based
- Which extensions are included, and which are available
Worth doing now if turnover has grown, you have moved premises, or your supply chain has changed.
FAQ
Is business interruption insurance compulsory?
No. Unlike employers’ liability, which is compulsory once you employ people, this is optional in law. A commercial lender or landlord may require it as a condition of the mortgage or lease.
Does it cover staff wages?
Usually yes. Wages are among the fixed costs the cover is designed to protect, since you may need to retain staff while closed. Check how your policy treats them, as some wordings insure wages separately on a dual basis.
Will it cover a home-based business?
It depends. Standard commercial cover assumes business premises. Some home business policies include a business interruption element, with different triggers and much lower limits. If you run the business from home, that is a conversation to have specifically rather than assuming your home policy handles it.
What happened with Covid?
Most standard policies paid nothing, because there was no property damage. The Supreme Court test case in January 2021 found that certain non-damage extensions did respond. Insurers have since tightened those wordings, which is exactly why the insuring clause deserves reading.
What should I keep in case I need to claim?
Accounting records that survive the event. If your only copies of the figures are in the building that burned down, proving your gross profit becomes considerably harder. Offsite or cloud-based accounting is a practical part of this cover working.
Business Interruption Insurance: The Bottom Line
Buildings and contents replace what was damaged. Business interruption pays the bills while you rebuild, and for most small businesses it decides whether there is still a business at the end of it.
Three things leave people underprotected: a purely damage-based trigger with no extensions, a 12-month indemnity period chosen on price, and a sum insured based on turnover or on one year’s gross profit when the indemnity period runs longer.
Start by reading the schedule you already have. If you are buying or renewing, use a commercial broker rather than buying on price, because this is the class where the wording decides everything and a cheaper policy that does not respond is worth nothing at all.
This article is general information about insurance in the UK, not advice, and it does not take account of your circumstances. Policy wordings, definitions and extensions vary considerably between insurers. Speak to an FCA-authorised broker or insurer, and involve your accountant in setting the sum insured, before relying on anything here.