He was expelled two years ago for running as an independent in the city's first mayoral elections.

Livingstone and Labour

Party member for 31 years Expelled in 2000 after standing against official party candidate Expulsions usually last five years It has been hinted the rules could be waived Livingstone applied for return June 2002 Next elections 2004

But Labour's ruling National Executive Committee voted by 17 to 13 not to change party rules to allow his readmission.

The news prompted the mayor's own deputy, Labour's Nicky Gavron to put herself forward as a possible candidate in the next contest.

Mr Livingstone reacted angrily to the decision to deny him readmission, which dashes his hope of standing as Labour's candidate in the 2004 mayoral elections.

"It is very damaging. The Labour Party has again ridden roughshod over the views of London Labour Party members," he told BBC London Live.

"Labour's vote in London will be split and the only beneficiaries of that will be the Conservative Party, who are already celebrating."

'Great mistake'

Labour chairman Charles Clarke said there had been concern Mr Livingstone would not toe the party line on issues like the private public partnership for the Tube.

Both Tony Blair and John Prescott voted against the mayor's readmission.

"The single most important consideration in people's minds was whether the application to rejoin was effectively an application that the Labour Party should endorse his independent candidacy for mayor of London," said Mr Clarke.

The Labour Party is now going to send itself into a spasm of internal fighting

Jeremy Corbyn Labour MP

NEC member Tony Robinson, who proposed the motion for Mr Livingstone's readmission, said: "Although I would like to have seen a different outcome, I still respect the reasons that people came to the choices that they did."

But Labour leftwinger Jeremy Corbyn, said it was "a very sad decision and a great mistake by the Labour Party".

He said: "They should have re-admitted Ken, so we can all fight on a united front in the 2004 mayoral elections.

"The Labour Party is now going to send itself into a spasm of internal fighting that is completely unnecessary."

Mr Livingstone's supporters had hoped the shock election of left-winger Derek Simpson as general secretary of the Amicus union, and strikes by council and rail workers, would work in the mayor's favour.

Ms Gavron said that a "great opportunity for London Labour Party members to select a candidate of their choice has been lost".

She added that she would now run because: "It is imperative that Labour values continue to form the basis for London's government."

'Made his choice'

The train drivers' union Aslef had written to Labour supporting Mr Livingstone's readmittance.

Karen Buck, the chair of the London group of Labour MPs, said she also hoped Mr Livingstone would be readmitted.

I do not see how we can have a candidate who is not Labour and who is anti-Labour in so many of his activities

Mike Gapes Labour MP

"Since being mayor he has acted very much in accordance with the government agenda, although there has obviously been major departure on transport policy," she said.

But Mike Gapes, Labour MP for Ilford, was among Labour MPs who thought Mr Livingstone should serve his full five-year expulsion.

"Ken Livingstone made his choice two years ago," he said, and party rules should "apply to everybody".

Mr Livingstone is currently launching his second High Court challenge to the government's part-privatisation of the Tube.

He is being challenged in the same court over plans to charge motorists �5 to drive into central London.

Mr Livingstone's eventual victory in the May 2000 poll followed a bitter battle within the Labour Party, which culminated in his expulsion.

The Labour Party's official candidate, Frank Dobson, came third place, a long way behind both Mr Livingstone and Tory candidate Steve Norris.

Senior party members were said to want Ken Livingstone to return to the fold to avoid a second such humiliation.