Former cabinet minister Peter Mandelson has denied rumours that he will help run Labour's general election campaign.
Mr Mandelson was a major architect of the New Labour project
Mr Mandelson, who is now a European commissioner, said he would cheer the prime minister on "from the sidelines", instead of playing a central role.
He told BBC Radio 4's Today programme a third term under Labour was a "very good idea".
The former spin doctor is widely regarded to have been a key architect of the New Labour project.
Mr Mandelson - a close friend and political ally of Prime Minister Tony Blair - said: "It's a very good idea that we have a third term Labour government led by Tony Blair for a full term."
He said it was good "not only for the sake of Britain's place in Europe", but also for Tony Blair's "policies for modernising our public services and strengthening the productive base of our economy".
He added that Britain should seize a referendum on the proposed European constitution as an opportunity to "re-cement" its relationship with Europe.
"Every generation or so in Britain, there needs to be an opportunity to re-state or re-cement our commitment to the European Union," said Mr Mandelson.
"This is one such opportunity and I think people need to seize it."
Mr Mandelson's elevation to European Union trade commissioner marked a remarkable political comeback after he resigned from the UK Cabinet in controversial circumstances on two occasions.