German utility RWE said its British business npower plans to cut about 2,500 jobs as it seeks to improve its financial performance, Sky News reported on Sunday, citing unidentified sources.

RWE said in a trading update in November that npower had lost about 200,000 customers in Britain since the start of the year, sending the division to an unexpected operating loss of €66 million ($73 million) in the first nine months of 2015.

In December it was fined £26 million ($37 million), the largest ever fine for a British power utility, after overcharging customers and improperly handling customer complaints.

Sky said the proposals were still being finalised but cuts would be made both among npower's directly employed workforce, at internal suppliers elsewhere in RWE and at outsourcing partners. RWE is due to report full-year results on March 8.

Npower's wesbite says that it employs about 9,700 staff.

Sky said that, including indirect employment, npower's operations account for around 11,500 jobs in Britain, meaning that the cuts would account for more than 20 per cent of its workforce.

Npower, one of Britain's six largest power companies, declined to comment on the report.-Reuters