Energy supplier RWE npower said Ofgem's report into its profits was "already out of date".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
A mixed week ahead weather wise with milder conditions for many towards the weekend
A damp start to the working week with brighter weather for most later in the day
Having a longer pregnancy also reduced the risk of suffering from post-natal depression, a study found.