The report suggests that a lack of progress in competitive energy markets has kept energy prices high by maintaining the influential position of dominant national utilities, with too few companies controlling too much of the market.

Powerful national champions are making it difficult for new entrants to gain a foothold in gas and electricity markets while a lack of cross-border trading has also exacerbated the situation.

The preliminary report steers clear of naming and shaming countries and utilities, but energy incumbents such as ENEL, Electricité de France and German players such as E.On are likely to be singled out when the final report is delivered sometime next year.