Ken: I said Brown was a liability and time has proved me right

In a wide-ranging interview to be published tomorrow, the former mayor of London claimed that Labour's unpopularity led directly to his defeat at the hands of Boris Johnson last summer.

Mr Livingstone also hinted that he would run as an independent if the party should "rig" its candidate selection process for the next mayoral race in 2012.

Mr Livingstone caused uproar within the Labour party when he called for Mr Brown to be sacked as Chancellor in 1998.

At the time, he accused Mr Brown of "economic misjudgments", "subservience to the City" by guaranteeing big bonuses, and claimed that Britain was "heading towards an unnecessary recession entirely of Gordon's making".

Most wounding of all, Mr Livingstone wrote in 1998 that Mr Brown could not " grasp the grand picture" and lacked an "instinctive feel for the huge sweep of movements in the global economy". He wrote: "Quite clearly, Gordon is not on top of macro-economic policy."

In last year's mayoral election, he ditched his criticisms as the pair campaigned against Mr Johnson.

In the interview the former mayor also claimed that Mr Johnson was too "centrist" to be re-elected and admitted that the Tory Mayor is not a "racist". However, he claimed that MrJohnson mimics foreign visitors to City Hall.

Mr Livingstone told Total Politics magazine he felt he had lost the mayoral election last year because of dire poll ratings for Mr Brown and Labour.

He said: "If you could have taken away the national dimension I think I would have won because Boris's negatives were more than mine. From the moment Boris [entered the running] my ratings went up and up. It was only in November they started coming down. I then realised it was just tracking the national party's polling. Immediately after the budget, Labour's figures and mine just went off a precipice.

"It was only really when I woke up and switched on the Today Programme and heard that Labour was on 24 per cent nationally, with the Tories on 44 per cent I realised I couldn't overcome that. I came in and started clearing my desk."

In remarks that will cause dismay in Downing Street, Mr Livingstone resurrected his long-standing criticism of MrBrown's chancellorship.

In what appeared to be an attack on Mr Brown's troubles over failing to regulate the City, he said: "I was very critical of the first two years. The passage of time has shown me to be right.

"I had fundamental disagreements throughout my eight years as mayor. I hoped when Brown took over, things would change more than they did. But I have not been massively surprised."

Mr Livingstone also said that Lord Mandelson was a "formidable operator, but I am not certain [his appointment as Business Secretary] sends the message of renewal that we want."

He attacked the Prime Minister's centralising approach adding: "97per cent of all tax collected in Britain is collected by Gordon Brown. When I told the Mayor of Moscow that, he said: 'That's worse than Russia under Stalin.' From the moment Thatcher got power everything was sucked up to the centre and it got worse under Blair and Brown."

Mr Livingstone said he was "as certain as you can be" that he will run for the Labour nomination for 2012 but suggested he could run as an independent as he did in 2000 when he lost the Labour nomination to Frank Dobson after the party changed its rules.

"I wouldn't have run the first time [as an independent] if I hadn't won [the Labour nomination], but I won and it was rigged. They have to have one member one vote. I will be happy to submit myself to one member one vote and abide by the result."