Centrica’s profits rose by 9% to £1.58bn for the six months to 30 June.

An unseasonably cold first half of the year saw profits from British Gas’ residential arm rise by 3% to £356m, up from £345m a year earlier.

Campaign group Consumer Futures said British Gas should use this opportunity to hold prices as a way of winning back consumer trust.

The company received criticism last winter after it hiked its gas and electricity prices by 6%, prompting it to say in May it would use any benefit from the extended winter to maintain its price competitiveness. It stopped short of actually announcing a price freeze.

Mike O’Connor, chief executive at Consumer Futures said: “Centrica, like other major suppliers, has benefited from the cold winter and the greater levels of demand. Wholesale gas prices have not risen significantly and their gas production and much of their generation business has done well. Those factors should give British Gas confidence to hold its prices.

“Energy companies have to make profits, but that should happen in a market that is fair, competitive and transparent.”

Earlier this week MPs criticised the lack of transparency in the energy market and urged regulator Ofgem to do more to bring back consumer trust and ease the burden of soaring energy prices on UK households.

Tom Lyon, energy expert at uSwitch.com, said:  “The fact that British Gas has absorbed increasing costs so far this year will be of cold comfort to consumers who may be fearing the worst – especially with rumours of price rises.

“Profits are up from last year, so we would urge British Gas to help quell customer’s fears and go one step further from its May pledge and commit to a price freeze for the rest of the year

“People are already starting to worry about next winter and the cost of their energy bills and high energy prices have a big impact on consumers.”