As for Livingstone, virtually all his Labour colleagues abandoned left-wing politics in the 1990s. As the markets boomed and globalisation seemed secure, their task became to imagine what middle-aged, middle-class swing voters in middle England wanted and give it to them. Or, as a shocked but still sardonic Alistair Darling put it to me on the night after the Lehman Brothers crash had ripped through the City, "All my life people have been saying to me: Alistair, stop being so left-wing, move towards the centre ground, become more moderate...Now they want me to nationalise the fucking banks!"

Livingstone, according to popular perception, has stuck to left-wing ideas all his life. Far from rejecting him, as political orthodoxy predicted they must, the voters saw him as a rare man of principle who defended the common people against the lies and machinations of the manipulative new elite.

The one unforgivable crime in the old politics was to run against your party. Livingstone ran against Labour to be Mayor of London — and, even more unforgivably, won. He pretty much endorsed Islamic Forum Europe, an offshoot of the extreme — Right Bangladeshi party Jamaat-e-Islami, as it fought Labour in London's East End. Instead of renouncing the turncoat, London Labour Party members voted overwhelmingly to put him forward as their official candidate for the May 2012 mayoral fight with Johnson.

It is fitting that the only two mayors of London have been Johnson and Livingstone. Elected mayors are almost Bonapartist in their disdain for the old checks and balances of liberal democracy. In London, the members of the assembly are not an effective legislature with the power to hold the executive in the form of the mayor to account. The only power they have is to amend the mayor's budget. They cannot do even that unless two thirds of members agree. Nor is the mayor constrained by his party. Prime ministers in parliamentary democracies are hedged and, on occasion, deposed by their colleagues. A directly-elected mayor can ignore all around him. He is not a primus inter pares but an elected dictator. He appoints his own cabinet of placemen and bureaucrats, who have no electoral bases of their own. He can do what he wishes until the viewing public votes on whether to throw him out of the Big Mayoral House or let him stay for another term.