Mr Ken Livingstone's decision to run - after much genuine agonising - has electrified the race for Mayor of London. Whether or not it portends the better government of the capital, the latest phase of Mr Blair's devolution project certainly rates high for entertainment value. The May 4th poll gives a glorious opportunity to a whole range of people who want to give the Prime Minister a black eye, and think he's had it coming.
Following yesterday's confirmation that he would run as an Independent, some commentators described Mr Livingstone's decision as always inevitable. However, sources close to him insist he was genuinely torn about whether to leave the party and break his word - with his partner and close friends acutely aware that the resulting Millbank campaign will be bitter, personal and dirty.
There had even been speculation that, at the last, the former leader of the Greater London Council would endorse Mr Frank Dobson in the cause of unity, take the grateful thanks of the party, secure himself as leader of the left and await the battle for the future succession. He himself had joked that - London Mayor apart - the only jobs which might tempt him were those currently occupied by Mr Blair and Gordon Brown.
But that really would have been fantasy politics. The party's gratitude would have been shortlived, and there was never any prospect of him being called to lead Labour in a post-Blair era. Moreover, London politics, and not Westminster, has always been Mr Livingstone's first love.
Announcing his candidacy yesterday, Mr Livingstone said the issue was whether the capital would have genuine self-government or merely the facade, with all real decisions still taken centrally. Since Mr Dobson's victory in the electoral college he had attempted to persuade Labour of two principles. First, that Londoners should not have imposed upon them a candidate they did not want. Second, that the breakup and partial privatisation of the Underground is overwhelmingly rejected by London voters. Without these principles, Mr Livingstone contended, "devolution and real self-government will be meaningless".
Having failed to persuade Mr Dobson to stand aside or to win policy concessions from the government, Mr Livingstone said he was "forced to choose between the party I love" and London's right to govern itself.
He acknowledged that this entailed breaking his previous commitment not to leave the party, and apologised, offering "no weasel words of equivocation". However, he added defiantly: "What I do not intend to do is take any lectures from those who have set new standards in ballot rigging."
An Evening Standard poll had shown 61 per cent of Londoners thinking he should run as an Independent, with just 21 per cent believing he should accept the electoral college "fix".
The votes of MPs were given a thousand times the weight of those of an individual party member. And Mr Dobson's final margin of victory owed everything to one Co-op branch which cast 8 per cent of the total vote in Mr Dobson's favour without balloting its members.
Control freakery: the charge that has followed New Labour's devolution trail from the attempt to block Mr Dennis Canavan in Falkirk to the imposition of Mr Alun Michael, the consequent failure to form a majority administration in Cardiff and Mr Michael's eventual replacement by Mr Rhodri Morgan.
Determined to shake off the "Blair's poodle" charge, Mr Dobson was setting out his stall yesterday, insisting he would be his own man, battling the Prime Minister and Chancellor for the resources London needs.
Voters may well respond to the argument that an effective mayor needs a good relationship with ministers, and that as mayor Mr Livingstone would find himself isolated and confined to the politics of opposition.
Some punters, on the other hand, might think the oppositionist option relatively costfree. Moreover, some Tory commentators fancy that even a Livingstone victory would not prove a disaster for Mr Blair - the battle with grungy Old Labour revealing ever more starkly the gleam of the New, and eclipsing the Conservative bid in the process.
There is serious danger for the Tories if this indeed becomes a purely Labour battle. Mr Steve Norris will hope to benefit from the split vote, and Mr Hague knows they must make a strong showing with a general election barely a year away.
However, if Mr Norris is not to win, the fascination will be to see who gets his second preferences - and the certainty is it won't be Mr Dobson.
For Tory voters know one thing about Mr Blair: he does not like to lose. And therein lies Mr Livingstone's biggest danger. Move aside, Dobbo, this is Tony's fight now.