Ed Miliband: I won't be back-seat driver for Jeremy Corbyn
Jeremy Corbyn is fit to lead the country, Ed Miliband has said as he ruled out being a "back-seat driver" for his successor as Labour leader.
Mr Miliband told BBC Radio 4's Today that Mr Corbyn had a large mandate which he was entitled to interpret in his own way and he would not provide a "running commentary" on his leadership.
Asked whether Mr Corbyn was capable of serving as PM, he said "of course".
Some MPs have privately questioned Mr Corbyn's suitability for high office.
Asked repeatedly on Sunday whether Mr Corbyn and his allies were fit to run the country, shadow business secretary Angela Eagle said all politicians have "strengths and weaknesses" and she was committed to "working with the people the party gives me to work with".
She said she would not answer a question that was purely designed to generate a media headline.
The Labour leader is at odds with many of his MPs over a number of issues, particularly defence and foreign policy, while his response to the Paris attacks and the terror threat facing the UK has been criticised by some of his MPs and shadow cabinet.
He is facing a potential rebellion by Labour MPs over airstrikes in Syria although there is broad support for his anti-austerity economic approach inside the party.
Mr Miliband, who stood down as Labour leader in May after the party's election defeat, said he would not be a "back seat driver" in his capacity as a backbench MP although he would speak out on issues that he felt strongly about, such as climate change.
Asked about the direction Mr Corbyn was taking the party in, Mr Miliband said he believed the Labour leader wanted a "fairer country" and he "admired" the fact he was drawing on a range of thinkers to develop its economic policy and address the key question of how to reduce inequality.
"He has set out what he believes his mandate is which is for anti-austerity, a different approach to foreign policy and participatory politics."
Asked whether Mr Corbyn's could win power, he said he was "not in the predictions game" and that was a matter for voters.
"In the end that is a decision for the electorate as I discovered to my cost. That is a decision the electorate have to make."
He added: "I am not going to be a back seat driver... I made a decision that as soon as I stepped down as leader I wasn't going to provide a running commentary on my successor. He is going to argue it in his own way."
But Mr Miliband said he believed the party was in a stronger state now, in terms of its membership, than it was going into the election.
"Jeremy Corbyn has doubled our membership and I, myself, have seen that in my constituency.
"I am seeking to work out how we use these new members so we can do what we didn't do fully under me which is become a community organisation which is a presence in communities up and down the country."
In the Today interview, Mr Miliband said climate change represented the "ultimate challenge" to politics and it was vital a deal was reached on limiting future global warming at a UN conference in Paris next week.
Mr Miliband, who was climate change secretary under Gordon Brown, said that if agreement wasn't secured to limit rises in temperature to a maximum of two degrees celsius it could prove "catastrophic".