Best for London

Without its current mayor, the capital would be a far less diverse and progressive city

London needs Ken Livingstone for many reasons. The first is that he is far and away the most qualified candidate. First elected to a local authority in 1971 (six years before Boris Johnson went to Eton), Ken has forgotten more about issues such as local government finance, transport economics and housing than most of us will ever know. And sheer volume of knowledge matters in a London mayor because they wield so much direct power (although, compared to the old Greater London Council, with a limited budget and a narrower range of legal powers).

A mayor without Livingstone's history would have found himself at the mercy of City Hall and Whitehall bureaucrats. Instead, his unsurpassed experience in local government helped give him the confidence to override officials and go for the congestion charge. His experience also enabled him to use his limited legal powers to maximum practical benefit for London. He has even persuaded government to increase his powers.

By contrast, Boris Johnson knows absolutely nothing, and cares even less, about local government. As for Brian Paddick, while he would make an excellent candidate for Metropolitan Police Commissioner, he knows almost nothing about issues such as local government finance.

Of the three white men standing for the three major parties, Livingstone is the one best placed to lead a city in which half the ethnic minorities of the entire country live and whose diversity is the foundation of its economic, social and cultural success. His commitment on race and diversity has been unswerving over a long career.

The leadership of all the major political parties now pay lip service to dialogue with Sinn Fein, race equality, feminism and gay rights. Yet much of the abuse that Livingstone received in the 1980s (and not just from the right) was precisely because of his stand on such issues.

And he has not just talked. He transformed the employment policies of the old GLC, opening up the top tiers of the council to women and black people and creating a cohort of senior officers, like Sir Herman Ouseley, who now occupy top positions in the public sector all over the country. The media sneered at the grants the GLC gave to black groups, but those grants empowered thousands of black Londoners and provided practical help to millions more.

The forceful leadership that Ken and others gave on race in the GLC era has ensured that London is at peace with its diversity, unlike many of our northern cities. In his first term as mayor, he introduced civil partnerships in London. Only then did the government find the courage to make such partnerships legal nationally. Would Boris Johnson have shown similar leadership? More recently, in the aftermath of the 7 July bombings in London, Ken's leadership helped to avert an anti-Muslim backlash. The idea of Boris Johnson (who is tone-deaf on race matters) in the same situation is alarming.

Some have tried to trash Ken's reputation on race and other matters, depicting the black-led voluntary sector as a cesspool of corruption. In the 1980s, the London Evening Standard (and its sister paper the Daily Mail) attacked him relentlessly on race equality, gay rights and feminism. Now they realise that, in London at least, the left has won the debate on those issues and are reduced to the politics of personal destruction.

One day a Barack Obama-style figure will blaze across London's firmament. Then it will be time to consider London after Ken. In the meantime the city needs him and his strong commitment on race and diversity. He brings experience none of the other candidates can match and results they could never have achieved.

When Livingstone stood for mayor as an in dependent he took on the new Labour machine at its most brutal and defeated it. It is 27 years since he emerged from the pack of London left young guns and seized leadership of the GLC.

He remains one of the best politicians of his generation.

Diane Abbott is MP for Hackney North and Stoke Newington

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