Tony Blair is "delighted a full policy debate is happening within the Labour party", he said today.
Pressed by Conservative leader David Cameron in prime minister's question time, Mr Blair said he supported moves by Alan Milburn and Charles Clarke to encourage a debate on Labour's future.
Earlier today, Mr Milburn and Mr Clarke formally launched their website The 2020 Vision, which they hope will serve as an "open forum for all those interested in progressive reform" and generate debate on the future of the Labour party.
Mr Cameron joined in speculation that The 2020 Vision is an attempt to encourage another New Labour candidate to contest the chancellor Gordon Brown for the Labour party leadership, prompting Mr Blair to defend his chancellor in the House of Commons.
Mr Brown has delivered a strong economy, the lowest interest rates and unemployment for 30 years, record employment and improved incomes for the poorest people, said Mr Blair.
Launching The 2020 Vision this morning, Mr Milburn warned, however, that Labour could not expect to be re-elected on the strength of the past ten years and instead needed to offer policies for the future, formed through a "full and open debate".
"The next election will not be won by relying on what we have done but on what we are planning to do," said Mr Milburn.
The party needs to build a "post Blair politic" addressing issues such as the environment, citizenship, rewarding aspiration, social mobility, work-life balance, a sustainable welfare state and public services, he added.
Addressing the carefully planned launch, Mr Clark told MPs and reporters that "politics is not a game, it is not a theatre in which certain individuals and policies go up on the merry go around of public opinion and media interest."
Instead it is about ordinary people shaping their society, he explained.
Mr Clark echoed Mr Milburn in arguing that Labour needed to provide policies on the "hard issues of the future", warning that past Labour governments had failed to make changes or offer people a reason to vote Labour again.
He warned: "We must not make that mistake another time and we should not underestimate the capacity of the modern Conservatives to mimic their predecessors and exploit any weaknesses we display."
In doing so the debate will focus on the interests of the country not the divisions of party activists, Mr Clark concluded.
Despite Mr Blair seemingly welcoming the debate, today's launch was attended by few MPs.