The "big six" energy firms made an average profit margin of 20 per cent for energy generation in their last financial year, according to figures released by energy regulator Ofgem.
The results are likely to fuel further anger over rising gas and electricity bills.
The key figures included:
- Profits in the domestic supply business increased by 75 per cent
- Companies made on average £53 per customer each year
- Average profit margins increased from 2.8 per cent to 4.3 per cent in 2012
- The big six made an average profit margin of 20 per cent for energy generation in the last financial year
More top news
Tesco recalls own-brand squash after customers complain of "disgusting taste" and parents worry it may have caused children's stomach upset.
Bradford City co-chairman Mark Lawn has blasted TV broadcasters over their FA Cup fifth round match choices
Face to face with 2 tons of unpredictable muscle is an awe-inspiring moment but within a few years it will be impossible, they will be gone.