British Gas claims it is the cheapest electricity supplier in the UK after slashing prices by 10 per cent.
The cut was delivered in response to falling wholesale electricity prices.
British Gas said it had sought to pass on savings to customers while maintaining the level of profitability needed for investment in securing future energy supplies.
It said the the price cut will impact on 4.5 million customers with immediate effect.
It follows the company's 10 per cent cut on gas prices, which took effect on 19 February this year.
British Gas says these two price reductions will save British Gas customers an average of £132 on their annual dual fuel bill.
Managing Director Phil Bentley said: 'British Gas is offering existing and new customers the cheapest electricity rates in the market place.
'We want to do what we can, when we can, for our customers.'
All British Gas electricity customers on standard tariffs - including those with pre-payment meters - will see the benefit of the price cut.