Labour has appointed a director of general election resources, in a move which will intensify speculation that Gordon Brown is to call a snap poll.
Mr Brown has enjoyed a lead over the Tories in recent polls
Businessman and former Tony Blair adviser Jon Mendelsohn will deal with improving the party's finances, membership and organisation.
The newly created role takes effect from the beginning of next month.
With Mr Brown buoyed by recent opinion polls, some observers believe he could call an election as early as October.
Mr Mendelsohn will report directly to International Development Secretary Douglas Alexander, the prime minister's general election coordinator, and Labour general secretary Peter Watt.
Labour said the voluntary role would be to "improve overall organisational efficiency and to develop the party's future financial strategies".
"He will work hand-in-hand with party staff on strengthening and extending our supporter base, seeking value for money in our expenditure and helping to build a party machinery that can best fight a general election, whenever the prime minister chooses to call it," it said.
Mr Watt said: "Jon is an experienced and successful businessman who is Labour to his core.
"Bringing him to work now on our preparations for the general election is an important step in our building for the future."
Mr Mendelsohn said: "As a lifelong Labour supporter and a passionate believer in social justice and equality, I am delighted to take up this post, helping the party prepare for the next general election.
"I hope that I can play my part in seeing the Labour government re-elected once again so Gordon Brown can continue to change Britain for the better."
A series of opinion polls has shown Labour maintaining a lead of six or seven points over the Conservatives since Mr Brown moved to 10 Downing Street.
A leaked memo last week showed the party's polling guru Lord Gould had advised Mr Brown in 2005 to go for "an early election after a short period of intense and compelling activity".
The prime minister has also asked Cabinet Office minister Ed Miliband to write an election manifesto.
But Downing Street has played down the prospect of an October election, stressing that the manifesto-writing process is likely to continue through the autumn.
Labour's finances are also in a worse state than those of the Tories, leading some commentators to suggest Mr Brown is more likely to call an election next spring.
Conservative leader David Cameron has said his party is ready for a snap poll.
Mr Mendelsohn was an adviser to Mr Blair from 1995 to 1997, when he left to co-found the LLM Communications lobbying firm.
He provided £5,000 to help fund Mr Brown's uncontested leadership bid.
He is quitting to take up the new role, Labour said, and would "have no commercial relationships with any previous clients".
Mr Mendelsohn is also treasurer of the Policy Network and Progress think-tanks.