David Miliband warned today that Labour risked three or four terms out of office if it picks the wrong leader to succeed Gordon Brown.
In an interview with the Daily Telegraph, the front-runner in the contest said he was "trying to persuade the Labour Party not to lose three or four elections before it bounces back".
The shadow foreign secretary described himself as "the unity candidate", with support from all sides of the party.
Speaking about his association with New Labour, Mr Miliband said: "I'm learning from the past but not living in it."
The new leader will be announced in Manchester on September 25 ahead of the party's annual conference.