David Miliband: My worst fears were confirmed when Ed lost the election

David Miliband has revealed how his "worst fears were confirmed" when his brother led Labour to the party's worst election result in nearly three decades.

The former foreign secretary, who moved to New York to head up the International Rescue Committee charity after narrowly losing to his brother Ed in the 2010 Labour leadership election, said he had been “very fearful of the consequences” of the lurch to the left in the last five years.

He said the election defeat, which saw the number of Labour MPs fall to a 30-year low of 232, was "doubly painful" because of his brother's involvement, but refused to attack him directly and insisted: "I don’t want him to be vilified.”

And although he revealed he had feared the direction Ed was taking the party was "courting disaster," he insists any sense of vindication is "massively outweighed by a sense of frustration and anger about what's going to happen to the country".

"There is no consolation in any sense of vindication, frankly, because I care about the country and I care about the party. It’s now facing ten years out of power," the older Miliband brother said in an interview with The Times.

“All my worst fears were confirmed,” he added. “I had spent the previous two or three weeks wondering whether in fact I was wrong to believe that you couldn’t suspend the laws of political gravity because the polls obviously suggested that things were close, but . . . the politics of our offer and our positioning made me very fearful of the consequences, and that was borne out.”

Lord Mandelson, echoing Mr Miliband's critique, said all the advances New Labour had made over combating its weakness over the economy, crime, public services and confusion over Europe “were being flushed away” under Ed's leadership.

Mr Miliband hinted at a return to British politics, but refused to be drawn on whether he still harbours ambitions of leading the Labour party. Addressing the future direction of the party, he said the challenge was how Labour becomes a "post-Blair political project rather than a pre-Blair political project".

He called upon the leadership contenders to apologise for the things New Labour got wrong but insisted: “We should liberate ourselves from the delusion that running away from three election victories is a route to success . . . it’s 50 years since Labour won a majority at a general election without Tony as leader. It’s important to have this in mind.”

Addressing his own future, he said: "I hope that I can use my voice now and again in the British scene," he said. "In terms of what I do next I’ll have to take some time to think about that.”