Lord Mandelson has said he will not rule out a return to politics.

The peer, who was considered the most powerful out gay man in Britain until Labour lost the general election, had to resign twice from the Cabinet during Tony Blair’s premiership.

He told Total Politics magazine that although he would not “sit by the telephone”, he would not rule anything out.

Lord Mandelson told interviewer Iain Dale: “I tend not to rule out of anything in politics, given my career, given my roller coaster career. Would you predict anything? I don’t think so. But I’m not going to sit by the telephone. I’m not going to hang around in expectation or with some sort of entitlement.

“I will find other things to do in my life. Things that I enjoy, things which I think are stimulating or important but also enable me to earn a living.

“If you were to ask me though, whether fundamentally I’d rather be in public service or the private sector… I’m a public service man. I was brought up in that way and that set of values and motives will never leave me.”

He added: “I’m not quite sure what [I will do], but amongst other things I have to earn a living. I don’t have an income any more.

The peer, who backed David Miliband to win the Labour leadership, said he would be loyal to Labour leader Ed Miliband, although he added that he felt “hurt” and “denigrated” by the latter talking about his”dignity in retirement”.

He said: “I felt as if I was being unfairly treated and packed off rather prematurely to an old folk’s home. I also thought to define himself against New Labour, as opposed to being a development of New Labour, was electorally unwise.

“But again, we’ve all moved on. What I’ve got to do now is remain a candid friend but also constructive and always loyal. I was always loyal.”

A fly-on-the-wall documentary about Lord Mandelson is to be screened on BBC4 this week.

‘Mandelson – The Real PM?’, filmed by Hannah Rothschild, shows the former business secretary in the eight months up to the May election.