The Labour Party’s Ed Miliband is currently favored to be prime minister after next month’s election in Britain, Betfair said.

The odds on a Miliband premiership are 10-11, equating to a 51 percent chance of the Labour leader becoming prime minister, Betfair said. A successful 11 pound bet on Miliband wins 10 pounds, whereas the same bet on David Cameron, rated as an evens chance, would win 11 pounds.

The favorites tag has changed seven times in the past week, Betfair said, underlining how the vote is the hardest to predict for decades.

A Labour minority government is the most likely single outcome of the May 7 election, with no party gaining a majority in the House of Commons, odds indicate.

The odds on a Labour minority administration narrowed to 7-4 from 2-1 following the BBC election debate on Thursday, Betfair said.