CUSTOMERS who buy their gas from Sainsbury's will pay 20 per cent less than British Gas customers on a similar deal despite the supermarket buying its supplies from... British Gas.

Price saving experts say new fixed tariffs launched by Sainsbury's Energy and British Gas today demonstrate why consumers must look beyond the ‘Big Six' to get the best deals.

Sainsbury's Energy launched two new tariffs - The Fixed Price February 2016 and the Price Freeze February 2016. British Gas launched the Price Promise February 16 tariff, too. All three price plans offer customers fixed prices until February 29, 2016.

But there is a big difference.

The Sainsbury's Energy Fixed Price February 2016 plan will cost the average medium energy use household £922 a year. It's a competitive tariff which works out just £9 a year more expensive than the current market leading Fresh Fixed Price January 2016 v10 tariff from Extra Energy.

According to figures supplied by GoCompare - the price comparison website - the British Gas Price Promise February 2016 tariff will cost the average medium energy use household £1099 a year.

The only difference between the two tariffs is that there is a £30 per fuel cancellation penalty if you leave the Sainsbury's tariff before the contract end date and there isn't an early cancellation charge with British Gas.

Jeremy Cryer, energy spokesperson at Gocompare.com, said: " Sainsbury's Energy use British Gas to provide their energy service. So British Gas customers are effectively paying close to a 20 per cent premium for having British Gas on the top of their bills compared to those who have Sainsbury's Energy on the top of theirs."

Even if a Sainsbury's customer left the tariff early, the £177 a year average difference between the two tariffs would still mean that the Sainsbury's customer was £117 a year better off.

Mr Cryer added: "These new tariffs demonstrate why customers must look beyond the Big Six to get the best energy deals.

"To all intents and purposes Sainsbury's Energy customers receive the same gas, the same electricity and the same service as British Gas customers but British Gas customers are paying a lot more for it. It's a clear example of an established ‘Big Six' provider trading on its brand to charge customers through the nose.

"Yesterday we heard from Ofgem that the major energy companies stand to make nearly 50 per cent more profit this year from UK households. Coming off the back of falling wholesale gas prices this will come as a major slap in the face to consumers struggling with their energy bills.

"Earlier this week EDF announced a pitiful 1.3 per cent cut to its' standard tariff gas prices, saving customers just £9 a year on average. It was the last of the ‘Big Six' energy providers to do so and one provider, SSE, even had the cheek to make customers wait until May before their 4.1 per cent drop comes into force. However, wholesale gas prices have fallen by 20 per cent and a typical supplier's wholesale costs have come down by £62 per customer per year.

"With ministers seemingly loathe or powerless to intervene, it's time for consumers to take matters into their own hands and ditch the greedy ‘Big Six' and check out the challenger brands. The five cheapest tariffs currently available are all short fixes from smaller energy companies with the cheapest from Extra Energy saving customers £413 a year against a typical bill. The best way for consumers to hit back at being milked of money by the energy fat cats is to ditch their expensive tariffs and switch to a more competitive deal from a less greedy challenger."