Gas and electricity bills are to rise for the second time in seven months.

Letters warning EDF Energy's 200,000 customers in Sussex about the increases from September 13 will land on doormats next month.

The rise comes after EDF raised the cost of electricity by 6.7 per cent and gas by 4.6 per cent on March 1.

Further rises of 3.8 per cent for electricity and 3.5 per cent for gas mean some customers will be paying almost £60 more than last winter.

A family of four could pay an extra £29 on its annual electricity bill of £294.60. The gas bill would rise by £30 to £394.

People living on their own can expect to pay an extra £16 for gas and £15 for electricity.

In 2002, EDF, which supplies customers in Brighton and Hove under the name Seeboard Energy, made group operating profits of almost £1 million a day. A spokesman for the company said the bigger bills were due to high fuel costs.

The cost of gas had risen by 25 per cent since the last increases were announced. Coal had risen by 20 per cent and electricity by 19 per cent.

EDF Energy has promised new customers its bills will be cheaper than British Gas between September 2004 and January 2006.

Labour Brighton Pavilion MP David Lepper said: "We are all used to annual increases but two in the past year to the tune of almost ten per cent does not seem to be a good way of doing it.

"I am concerned about people on a low income and elderly people living on their own.

"I will certainly be wanting to ask EDF some questions."