David Miliband has not ruled out a return to British politics, he indicated in an interview for fashion magazine Vogue.

Asked whether he could envisage re-entering the UK political fray, the former foreign secretary - who quit Parliament in 2013 after losing to his brother Ed in the contest for Labour leader - would say only: "I don't know, is the answer."

While Ed prepares for the pressures of a general election showdown in the bearpit of Westminster, the elder Miliband brother indicated that he appreciates being more "anonymous" as the New York-based chief executive and president of the International Rescue Committee charity.

"One of the attractions of the job is - though it is incredibly important to tackle poverty in stable states, we are focused on tackling poverty and threats to life and limb in unstable states - but while on the one hand it is satisfying to be life-saving, on the other you do have this sense of marginality," he told British Vogue.

"You're certainly more anonymous in New York. You've got the occasional British tourist, of course, and then you've got people who watch BBC World, but in a city of eight million people, yes, I'm pretty anonymous."

Mr Miliband refused to make any comment on his brother's performance as Labour leader, saying: "I can't say anything, because anything I say plays into the whole narrative. And I made an absolute commitment to myself not to play into the story ... It's not good for him and it's not good for me for this to became a story."

Asked about a possible return to politics, he said: "Ummm...I don't know, is the answer.

"It was obviously a big move to come to the States. I had a very good run. Obviously I still care about the country, but I've come here to make a success of this job.

"Whenever anyone asks me when I decided I wanted to go into politics, I always say: `What do you mean, when did I decide? I still haven't decided!' Evidently it's not all written down on a sheet of paper. It feels like I'm in the right place at the right time."

David said that absence from London had made his "heart grow fonder", but admitted he appreciated the greater straightforwardness of people in New York.

"People in New York have been very genuine," he said. "You know how people in London say, 'Oh you must come for dinner' and don't always mean it? Well, there's a sincerity in New York which I'm struck by.

"But, I mean, we've got this fantastic network for friends (in London), people we are incredibly close to, and you worry a lot about not losing those roots and links and commitments, and you want to nurture them, and I don't want to cast Britain in a negative light at all because absence makes the heart grow fonder, don't you think?"