British Gas and ScottishPower are established giants in the UK domestic energy supply market. They formed part of what used to be called the “Big Six” group of large energy suppliers that used to dominate the market, alongside EDF Energy, E.ON, Npower and SSE. This has changed with Octopus Energy has the current market leader, followed by British Gas, E.ON, OVO Energy, EDF Energy, and ScottishPower.
But what do these 2 legacy suppliers offer? Established in 1990 in Glasgow, ScottishPower is one of the UK’s largest producers of electricity from offshore wind. As well as supplying a range of fuel tariffs, ScottishPower sells packages for boiler and appliance servicing through insurance and repair firm Domestic & General.
British Gas has a longer history, beginning life in 1812 as the Gas Light and Coke Company, the world’s first public utilities company. Today, like ScottishPower, it offers a wide range of energy tariffs, including some time-of-use tariffs designed to cater to electric vehicle owners who want to charge their vehicles at home during “off-peak” periods.
Read on to find out how these 2 firms compare when it comes to tariff types, value, customer service and green credentials.
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| Finder score | ★★★★★ | ★★★★★ |
| Manage account via app | ||
| Can offer Warm Home Discount | ||
| Percentage renewables (electricity) | 76% | 36% |
| Compare | Compare |
This will heavily depend on your tariff, location and usage, but it’s fair to say that neither of these is likely to be the cheapest option available. Large legacy suppliers tend to charge more for energy than smaller “challenger” brands.
While both companies offer some competitive benefits, both firms’ customers are also liable to face price rises in future, as market regulator Ofgem is increasing the energy price cap, giving energy firms the green light to increase their prices from October 2021. This is likely to hit both “default” variable and fixed tariffs over the coming months. The best way to find out which is better value for you is to run an energy comparison, using a postcode checker like the one on Uswitch's comparison service.
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| Finder score | ★★★★★ | ★★★★★ |
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| Manage account via app | ||
| Manage account by telephone | ||
| Live chat support available | ||
| Email support available |
According to data compiled by the charity Citizens Advice for January to March 2026, an average of 61.8 per 10,000 ScottishPower customers were escalated to a third party, including the Energy Ombudsman, a dispute resolution organisation recognised by the energy industry.
Over the same period, an average of 68.7 per 10,000 British Gas customers could not be resolved without outside involvement.
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| Green tariffs | ||
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| Dual fuel deals |
Aside from the usual selection of “default” standard variable and fixed deals, both of these suppliers offer a broad range of tariff types designed to cater for a range of circumstances. Both firms also offer pre-payment tariffs, which can help households better control how much they spend on their energy usage. But it’s worth bearing in mind that pre-payment tariffs typically end up costing customers more over the long term when compared to households who pay for their energy via direct debit and are supplied through a credit meter.
Both suppliers offer fixed tariffs that charge exit fees and those that don’t. If a British Gas customer wishes to leave a fixed tariff early and is subject to an exit fee, they typically may need to pay £50 per fuel (depending on the length of plan) to be released from their deal. ScottishPower customers who want to be released from a fixed tariff that charges exit fees will need to pay £50 per fuel.
Under the Ofgem rules, fixed tariff exit fees don’t apply if you decide to leave within the final 49 days/7 weeks.
While these 2 giants offer broadly the same range of energy tariffs, the typically lower exit fees charged by ScottishPower give it the edge. ScottishPower also offers tariffs that help to support the charity Cancer Research by making a donation on a customer’s behalf for every month they remain with the supplier.
If you’re conscious of your carbon footprint, it’s worth investigating how forward-thinking a supplier is when it comes to green energy.
Data from British Gas’s Fuel Mix from 2024 – 2025 show that British Gas’s supply of electricity from renewable sources was 35% (UK national average is 42%), while data within the same period for ScottishPower show that 7% of their electricity came from renewable sources.
ScottishPower is the first integrated energy supplier to focus on 100% green electricity generated from their onshore and offshore UK wind farms, selling their fossil fuel power stations. However, for standard customers, ScottishPower’s delivers higher emissions per kWh (468g) compared British Gas (53g) as their energy sources come from low-carbon sources.
It’s also worth noting both ScottishPower’s green tariffs and British Gas business tariffs promise to source all their fuel for electricity supply from 100% renewable sources.
While neither firm is likely to be the cheapest in your area, it looks like British Gas takes the lead when it comes to the overall rankings. This is mostly due to the fact that it appears to have more satisfied customers than ScottishPower, according to complaints data from Citizens Advice. In most other areas, the 2 firms are broadly similar in what they provide their customers. But while price is likely to be a key factor in helping potential customers decide to make the switch, customer service is also a major decider – that’s why the crown goes to British Gas this time.
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