Millions of British Gas customers will see their gas and electricity bills rise today as its latest round of price hikes takes effect.

Customers will see their gas bills rise by an average of £78 a year and the cost of electricity will go up by around £37. British Gas has now hiked its charges three times in the last 12 months. Gas customers are paying 57 per cent more than they were a year ago and electricity customers have seen their bills soar by 52 per cent.

Other energy suppliers have also hiked their bills, with Powergen announcing another increase last month. However, Uswitch.com, a comparison service, said that British Gas remains the most expensive provider, charging about 18 per cent more than its rivals for gas and 17 per cent more for electricity.

Even so, British Gas remains the country’s biggest supplier, with 52 per cent of the retail gas market and 23 per cent of electricity market. Paul Green, chief executive of Energyhelpline.com, another price comparison service, said the latest round of price rises meant that more people would become "fuel impoverished" meaning that more than 10 per cent of their annual income is spent on fuel.

"This winter is going to be the worst winter yet," he said, "as the recent price rises start to take effect, especially for the more vulnerable members of our communities, such as the aged and families on low incomes."

Consumer groups urged people to consider switching suppliers to get a cheaper deal. Customers who have never switched could save an average of £313 a year by moving to the cheapest provider in their area, according to Uswitch.

Some analysts believe there are further price rises ahead as wholesale prices continue to climb. Energyhelpline.com, a comparison service, is predicting another wave of hikes next month. Fixed and capped-rate deals may therefore be worth considering as they will protect you from further rises. However, they are more expensive than the cheapest variable rate tariffs so you do pay a premium for that security.

Powergen’s Capped Dual Fuel deal costs the average household £1,019 a year, but consumers would pay £944 a year with its standard variable rate gas and electricity tariffs. And if consumers opted for the cheapest provider, Atlantic Electric, they would pay only £779, according to Uswitch.

Some people will be prepared to pay the extra, given the extent to which prices have risen over the last few years. If there are further rises over the coming months, that premium could well be wiped out.

However, industry watchers, including Sir John Mogg, chairman of the energy regulator Ofgem, believe energy prices will start to drop back later this year or early next.

If prices fall, consumers signed up to a fixed-rate product are not usually tied into a contract so they could change to a supplier with a variable-rate deal.