By BBC News Online's Mark Davies

Tony Blair has been warned by left-wing London mayoral candidate Ken Livingstone that Labour's troubles in Wales could be repeated in London - with even worse consequences for the party.

Mr Livingstone, one of three candidates hoping to be Labour's candidate for London mayor, told BBC News Online a similar crisis to that in Wales could easily happen in the city.

He said anger over the way the Labour race has been handled could lead to a "backlash" against the party and lead to Conservative candidate Steven Norris being elected London mayor.

The left-wing Brent East MP was reacting to the resignation as Welsh First Secretary by Alun Michael.

Mr Michael took up the post after a controversial leadership contest with fellow MP Rhodri Morgan, who was seen as the favoured candidate of Labour's grassroots supporters in Wales.

There was anger in Wales among some Labour members, who believed Mr Michael had been imposed on them as the favoured candidate of Mr Blair.

Mr Livingstone and his fellow candidates for the Labour nomination, Frank Dobson and Glenda Jackson, will hear this month who has been successful in the controversial contest.

The system set up to elect the candidate has also been widely criticised, with the candidacy of former health secretary Mr Dobson - Mr Blair's favoured candidate - compared to Mr Michael's in the Welsh elections last year.

And Mr Livingstone said Mr Michael had been a "scapegoat" of a system set up to ensure Mr Blair's favoured candidate was elected.

He urged Mr Blair to learn from the crisis in Wales.

'No doubt'

And he warned: "It would be even worse in London. There won't be a backlash eight months after the election like there has been in Wales.

"The backlash will come on polling day for Labour. There is not the slightest doubt that what we have seen in Wales could be replicated in London.

"If Londoners are unhappy with the way the contest has been run, they will punish Labour."

He said that could let in Mr Norris, who Mr Livingstone said was positioning himself as a "middle-of-the-road" candidate to try to capitalise on Labour's problems.

Mr Livingstone said: "What happened in the election in Wales is that the Labour vote slumped by 17%.

"If that happens in London we will lose the election."

Mr Blair has urged his party not to back Mr Livingstone's attempt to become Labour's mayoral candidate.

Maintained lead

The Labour contest - which is being decided by an electoral college of votes from members, MPs, MEPs and unions - has been dogged by controversy and accusations of dirty tricks as the prime minister and other senior Labour figures have sought to halt the Livingstone bandwagon.

But the popular left-winger and opinion poll front-runner for London mayor has maintained his lead over Mr Dobson.

Like Mr Livingstone, Mr Morgan was a popular candidate among party members in the Welsh elections, polling 64.3% of the votes cast by the 25,000 party members in Wales compared to Mr Michael's 35.6%.

But he polled fewer votes than Mr Michael in the union and MPs and MEPs sections of the electoral college.

The mayoral election in London takes place on 4 May.

Other candidates include Liberal Democrat Susan Kramer and Darren Johnson of the Green Party.