Labour party membership could disappear within seven years if the current rate of decline continues, a candidate for the deputy leadership warned yesterday.
Jon Cruddas, MP for Dagenham and a former Downing Street aide, said the party had lost 160,000 members between 2000 and 2006 - the equivalent of one every 20 minutes.
He warned Labour must rally members and re-engage with the electorate through community campaigning, saying: "You need to build it from the bottom up. Activity on the streets, a local presence, continuously, year on year and not just at election times."
However, Labour party chairwoman Hazel Blears accused Mr Cruddas of a "sensational" use of statistics and noted that the fall in membership last year of 3,348, to 198,000, was the lowest since records began in 1991.
"Our membership is broadly the same as other political parties, and not just in this country but around the world there is a lack of political engagement," she said.
"And I think that the process we are undertaking to involve the public should also help us to reinvigorate our party politics."
Mr Cruddas - who is up against Peter Hain, Harriet Harman, Hilary Benn and Alan Johnson for the deputy Labour leadership - has built his campaign on the need to re-engage with traditional Labour supporters.
Yesterday Downing Street unveiled plans to choose 100 members of the public to help inform government decision-making. The so-called "people's panels" would put themselves in ministers' shoes on a broad range of policy proposals.
But Mr Cruddas warned: "You are not going to resolve this from Westminster - you are not going to resolve this simply through edicts from the centre."
He said: "The days when all you needed was a good spin operation are over - we have to get back to local, pavement politics."
His comments come after claims in The Times yesterday that former home secretary Charles Clarke believes neither Tony Blair nor Gordon Brown, his expected successor as prime minister, have given voters a good reason to support Labour again.
Since leaving government in May, Mr Clarke has made a series of speeches setting out where he thinks New Labour should go, and the newspaper reported that this comes from concern about the party's ability to meet the challenge of David Cameron's Conservatives.