David Miliband 'passionately' wants brother Ed as prime minister
David Miliband has said he "passionately" wants Labour to win the general election and for his brother to become the next prime minister.
In an interview with the Financial Times, the former foreign secretary said his brother Ed, the Labour leader, had "clarity, vision, determination".
He also said it would be "unbelievably stupid" for the UK to leave the European Union.
The Miliband brothers contested the Labour leadership in 2010, which was eventually won by Ed, the younger of the two.
David, who left UK politics when he resigned as MP for South Shields in 2013, told the FT: "I passionately want Labour to win - and Ed to win [the general election]."
There has been recent speculation over the Labour leader's ability to take his party to victory in the general election next May, with reports that some backbenchers wanted him to resign.
But when asked if his brother would make a good prime minister, David replied: "Of course. I would know that better than most."
Questioned about his brother's relevant qualities for the post, he added: "What I would say is that the clarity, the vision, the determination, those are all important qualities.
"But, equally, I have made it a rule not to insert myself into the political dynamic for two reasons. One, I have got a job that requires me to work with the current government.
"And, two, I am trying to run a charity, not a political party. My experience is that anything I say gets taken out of context."
Mr Miliband was also asked about Prime Minister David Cameron's plans, should the Conservatives win the next election, to hold a referendum in 2017 on whether or not the UK should remain in the European Union.
There was a "real danger" that the prime minister might "paint himself into a corner", Mr Miliband said.
"Those on the pro-British - as I call it - pro-European side of the argument have got to make the case that we get far more from being at the table than shouting with a loud hailer outside the room.
"I have this residual faith in the common sense of the British people that generally they don't do stupid things. And it would be unbelievably stupid to walk out of the European Union."
When asked if he could ever envisage a return to UK politics, Mr Miliband pointed out that two years ago he had no idea he would be in his current post.
"You just don't know, do you," he said.