Labour must try and do better than a "dodgy 0-1 away win" in 2015, Labour's policy co-ordinator Jon Cruddas has said.
Polls suggest the election in May will be extremely close, with Ukip and the SNP chipping away at Tory and Labour and Lib Dem support.
The shadow cabinet minister said Labour should not shy away from thinking big and taking bold decisions over the next five months as it "re-imagines" what social democracy is for.
Speaking at the Institute for Government think-tank on Thursday, Cruddas said Labour could either say the challenges were "all to big" and wait until it was in power to address them, or "get our hands dirty".
"You celebrate the complexity and difficulty of it," he said. "That's the hallmark of a mature prospective government." With the election in May, Cruddas acknowledged "we haven't got long".
The Dagenham and Rainham MP noted that traditionally Labour spent a long time in Opposition after losing power and was hoping to buck that trend this time. The party under Blair and Brown, he said, "had been somewhat disfigured by gang wars and drive by shootings so we had to reestablish the character of the party".
Looking back at the party's history, he said: "If we lose we then get into some big factional fight. We ignore the electorate, we ignore the business community, we ignore some of these contemporary challenges, funnily enough, the electorate ignore us."
He said the digital age gave Labour a chance to refashion what it was for. New Labour, he said, had been focused on ensuring the decline in workers' wages was supplemented by tax credits through a compact with business. "The question is, what happens when the music stops, November 2008, the money stops," he said. "You have to reconsider what you are for when there is little money."
Cruddas said Labour should now be focused on ideas of "democracy" and "power" rather than "the metric of cash transfer".