Energy supplier RWE npower said Ofgem's report into its profits was "already out of date".
The energy supplier said in a statement: "RWE’s power stations in the UK made a loss of £51 million, a far cry from a 20% profit margin.
"For supplying Britain’s homes and businesses with electricity and gas, npower made a profit margin of just 3p in the pound”.
More top news
Lawyers in the US are attempting to seize £190,000 in life insurance taken out by San Bernardino Syed Rizwan Farook.
An Australian-style points-based immigration system could be introduced if Britain votes to leave the EU, Brexit campaigners have revealed.