Speaking to ITV News, David Blunkett has told those criticising Ed Miliband to "get off your bum, and get out there and campaign."
The veteran MP - who has announced he is standing down - said: "My message to people who are chipping away at Ed Miliband: forget the idea that someone else is going to step forward or there's going to be some kind of peremptory election. There isn't.
"So get off your bum and get out there and campaign. Not for any individual but for the values we espouse."
Mr Blunkett added that if Labour were to lose next year's election they could be out of power for a very long time.
More top news
The FBI is believed to have fitted a tiny microphone into a hotel key fob to spy on officials.
A woman who refused to get married as a 'fat bride' tells GMB she shed six stone after a nasty jibe about her weight left her in tears.
A car ended up on a motorway embankment and got stuck in the trees after the driver lost control.