British Gas Deemed Rates

Last updated: April 2026

British Gas supplies more commercial properties in the UK than any other company. That’s partly history and partly scale. It means that when you move into a shop, office, or industrial unit, there’s a decent chance British Gas is already the supplier. And if you haven’t arranged a contract, they’ve already started billing you at their deemed rate.

Nobody rings you up to mention this. The lights work, the heating fires up, and the bills start arriving. It’s only when you look at the numbers that something feels off. The unit rate is higher than anything you’d find if you went looking for a deal. The standing charge is too. That’s because deemed rates are the most expensive tariff type across all suppliers, and you didn’t even choose it.

How Businesses End Up on British Gas Deemed Rates

Three routes, and none of them are deliberate.

The most common is moving into new premises. British Gas was the incumbent supplier, the previous tenant left, and the supply kept running. From the moment you used a single kilowatt, British Gas treated you as a new customer on their default deemed tariff. This is especially common on high streets and in retail parks where British Gas has supplied the property for years.

Second is a change in your business’s legal structure. Switching from sole trader to limited company, changing the company name, or any restructure that makes you look like a different entity to British Gas. They treat it as a new relationship and start a fresh account on deemed terms. Even if you’ve been paying them for years under the old setup.

Third is a gap between contracts. Your fixed deal ended, renewal didn’t happen in time, and instead of a clean rollover British Gas moved the supply onto their default pricing. Whether that’s technically deemed or out-of-contract depends on the specifics, but the result on your bill is similar. Our deemed contracts guide covers the difference in detail if you want to check which applies to you.

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What British Gas Deemed Rates Cost

British Gas publishes their deemed rate cards online and updates them quarterly. That transparency is helpful, but deemed rates across all suppliers are consistently much higher than negotiated fixed deals. British Gas is no exception.

We’re not listing specific unit rates here because they shift every quarter and vary by meter type and region. A business in Birmingham won’t see the same numbers as one in Edinburgh. What stays consistent is the gap between deemed pricing and what you’d pay on a fixed deal. It’s substantial, and it applies to both the unit rate and the standing charge.

Check your latest British Gas bill. The tariff name should be visible on the front page. If it says “deemed” or “standard variable”, you’re on default pricing. Compare your unit rate per kWh and daily standing charge against what’s available on a fixed contract. That comparison usually tells you everything you need to know about whether it’s worth making a phone call.

Because British Gas has a wider range of fixed products than most suppliers, the options for stepping off deemed rates are actually better with them than with smaller companies. One, two, and three-year fixes are typically available. But you don’t have to stay with British Gas. You can move to any supplier you like.

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How to Switch Off British Gas Deemed Rates

You’ll need your meter numbers first. For electricity, that’s your MPAN. For gas, your MPRN. Both should be printed on your British Gas bill. If they’re not obvious, our MPAN and MPRN lookup guide explains exactly where to find them and what format to expect.

Once you’ve got those, you can start comparing fixed deals. You’re free to stay with British Gas on a negotiated contract or switch to another supplier entirely. There’s no exit fee on a deemed rate. No notice period beyond the standard 28 days. No penalty of any kind.

If you’re a new tenant, British Gas may ask for a copy of your lease or a letter from the landlord before processing changes to the account. Having that paperwork ready speeds things up.

The switch itself is straightforward. The new supplier handles the transfer, British Gas sends a final bill based on a closing meter reading, and your supply continues without interruption. Most switches complete within five to ten working days. If you’d rather get quotes from multiple suppliers at once, you can compare business energy prices through a broker instead of contacting each one individually.

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Deemed rates vs a fixed contract: at a glance

Here’s how the two arrangements compare on the points that matter most to business customers:

Things to consider before switching

Where deemed rates work in your favour:

• There’s no minimum term and no exit fee, so you’re free to move whenever a better-fit contract comes along.
• Only 28 days’ notice is needed to switch supplier, which gives flexibility if your circumstances are changing.
• Your supply keeps running from day one when you take on a new property, even before you’ve looked at contract options.

Where a fixed contract tends to suit better:

• Unit rates and standing charges are locked in for the contract term, which makes budgeting and forecasting easier.
• Contract length, green energy options, and payment terms can be tailored to how your business actually uses energy.
• You’re no longer exposed to quarterly rate updates — the terms you agree are the terms you pay for the duration.

FAQs

What are British Gas deemed rates?
Deemed rates are the default tariff British Gas applies when you use gas or electricity at a property without an agreed contract in place. They’re the fallback pricing that keeps your supply running until a contract is set up.

How do I know if I’m on a British Gas deemed rate?
Check the front page of your latest bill. If the tariff name shows “deemed” or “standard variable”, you’re on default pricing. Comparing it to a current quote for a fixed deal is the quickest way to see what’s available.

Can I leave a British Gas deemed rate at any time?
Yes. Deemed tariffs have no lock-in, no exit fee, and no minimum term. The standard 28-day notice period applies and you can move to a fixed deal with British Gas or any other supplier whenever you’re ready.

How do deemed rates compare to a fixed contract?
Deemed pricing is set by the supplier rather than negotiated, so the terms aren’t tailored to your business. A fixed deal gives you price certainty over the contract term, which is usually why businesses choose to move onto one.

How do I switch off British Gas deemed rates?
Find your MPAN for electricity and MPRN for gas on your British Gas bill, then compare fixed deals. You can stay with British Gas or move to any supplier. The switch usually completes in five to ten working days with no interruption to your supply.

Do I have to stay with British Gas to get a better rate?
No. A deemed rate doesn’t tie you to British Gas in any way. You’re free to compare options across the whole market and choose the supplier and contract length that suits your business best.

Can British Gas put me on a deemed rate without letting me know?
In practical terms, yes, in three situations: moving into a property British Gas already supplies, changing your business’s legal structure, or letting an existing contract lapse without renewal. This reflects how deemed tariffs work industry-wide — the default rate applies by design when no contract is in place.

How often do British Gas deemed rates change?
British Gas publishes their deemed rate card online and updates it quarterly. A fixed contract locks in your unit rate and standing charge for the full term, which some businesses prefer for budgeting.

Key Takeaways

✓ British Gas is the most common default supplier for UK commercial properties, so deemed rates affect their customers more than any other supplier

✓ You’ll end up on deemed rates after moving into premises, changing business structure, or letting a contract lapse

✓ Prices are significantly higher than fixed deals and can change every quarter

✓ You can switch at any time with no exit fees and no lock-in

✓ British Gas offers a wide range of fixed products, but you’re free to move to any supplier

✓ Find your MPAN and MPRN, compare what’s available, and the switch takes around five to ten working days

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