Two former cabinet members have called for a full debate on the future of the Labour party, in what is being seen as a further challenge to Gordon Brown's smooth transition to party leader and prime minister.
Alan Milburn and Charles Clarke have emailed all Labour MPs and peers urging them to help "move the debate forward" on the future of the party and government.
"After ten years in office we will need to demonstrate that we have the vision and the policies to successfully meet the future challenges faced by our country and the wider world," they wrote.
Their email follows the Conservative's increasing success in opinion polls, with one ICM/Guardian poll finding that support for Labour falls when Mr Brown's name is attached to the party.
Mr Milburn, regarded as a firm ally of Tony Blair, and Mr Clarke, who was last year sacked as home secretary, claim there is an "enormous appetite" for such a debate within the parliamentary labour party.
"There will, of course, be many different points of view about the future direction we should take as a party but we believe the critical thing is to develop an open process for ideas and views to be aired," they wrote.
It is reported that the pair met with the chancellor to discuss the email and he is said to support the idea of more debate. Speaking on BBC Radio 4's World At One, David Blunkett also said he welcomed the debate as part of a wider policy review.
However, some suggest the email is designed to provoke another new Labour candidate to stand against Mr Brown for the party leadership and other senior MPs are thought to be keen for another cabinet-level candidate to contend the leadership.
Last week, former environment secretary and Blairite critic Michael Meacher announced he will be standing for the leadership. Backbench left-winger John McDonnell also plans to stand against Mr Brown.
It is not yet known if either candidate will receive the necessary support from 44 MPs to make it onto the ballot and Labour colleagues, including Tony Benn, have urged Mr Meacher to withdraw his candidacy to support Mr McDonnell.