Troubled nuclear power generator British Energy today announced a steep rise in operating losses and admitted that it was facing a challenging second half.

The group said increased pension costs, an inability to take advantage of electricity price rises and higher depreciation charges had had a "significant adverse impact" on its profitability and cash flow in the first half to September 30.

Group losses after tax and one-off items came in at £262 million against £79 million last time.

British Energy added that the rest of 2004/5 would be difficult due to a number of unexpected shutdowns at its plants since mid-March and delays in reopening power stations at Hartlepool and Heysham.

"The directors consider that the outlook for the company's financial and trading prospects for the remainder of the financial year will be challenging," it said.