Tomorrow's election for the Mayor of London is the culmination of a uniquely engaging contest, focused on two of the most charismatic individuals in British political life, Ken Livingstone and Boris Johnson.

Mr Livingstone has tried to present the election as a choice between success and catastrophe - his victory, or Mr Johnson's. It is indeed a crucial choice, but not that one. London's Mayor has real power in relatively few respects: notably, policing, transport and planning. In these areas, the two main candidates' policies have sharp differences. But the contest between Ken and Boris represents two different ideas of the city, two opposite approaches towards the governance of London. And the central issues involved are competence and honesty.

This newspaper backed Mr Livingstone in 2004. But after two terms in office, there is no doubting what his rule represents. He sees City Hall as the centre of patronage and control, where he, as Mayor, plays various client groups - defined in terms of ethnicity, religion, gender - off against each other. The effect of the Mayor's patronage is divisive, giving the impression he favours every religious and ethnic group above his own. And his administration is profoundly personal, employing large numbers of bureaucrats committed to his interests, as well as an insular personal clique. Where his administration once seemed radical, at the end of two terms it appears - like the candidate himself - tired as well as arrogant.

Mr Livingstone projects himself as the more experienced and competent candidate. It is true that he has done quite a lot - but nowhere near as much as he claims. Indeed many of his achievements are double-edged. In the aftermath of the July 2005 London bombings, he articulated effectively the city's outrage - though his role as a unifier has been compromised by his relationships with terrorist sympathisers such as Yusuf al-Qaradawi. He played a major part in attracting the Olympic Games to London, although his admission last week that he achieved this by grossly and deliberately underplaying the likely cost of the Games, thereby conning the taxpayer, severely tarnishes this victory.

The congestion charge, a bold initiative, has become steadily less effective in tackling the paralysis of London's roads: traffic speeds are now almost back to pre-charge levels. He raised the charge from £5 to £8, breaking his original promise not to do so, and extended it westward last year, riding roughshod over the findings of his own public consultation. Businesses have suffered as a result. But he shows no sign of taking notice of objections that do not fit his pre-conceived plans.

Meanwhile, there are far more buses, but at vast extra cost - currently £625 million a year, 11 times the subsidy in 2000. Indeed, buses operate at less than 30 per cent capacity, while nearly 10 per cent of passengers on bendy buses get away with not paying their fares, at an annual cost of £6 million. Fares have risen above inflation, and those unable to use the Oyster card have been hit with swingeing fare increases on both buses and Tubes - another broken promise.

Mr Livingstone has not delivered on affordable housing, with new developments including just 34 per cent of affordable units - the same number as eight years ago - rather than his promised 50 per cent. His relationship with developers has been worryingly cosy, involving undeclared donations: the Mayor has enthusiastically endorsed plans for high-rise buildings that will dramatically alter London's skyline, not just in the City but in the suburbs too. This trend would be accentuated by the Mayor's newly acquired powers to force through "strategic" projects against the will of councils who turn them down: if Mr Livingstone is reelected, it will change the face of London.

LET US not forget either that Mr Livingstone has a marked tendency to take the credit where it is not his. Contrary to his claims, the City's economic boom has had little to do with him. Neither does the fall in overall crime rates - although at the same time, he has eschewed responsibility for London's gang violence and social division.

But this race is not just about competence. Honesty has not been Mr Livingstone's strong suit either. He has broken promises - on fares, on the congestion charge, on retaining Routemaster buses. He has also broken his original commitment not to stand for a third term - a more profound mistake. As he himself said in 1998: "Corruption tends to flourish the longer an incumbent is able to hold on to power." The problems surrounding Lee Jasper, his race adviser, and the police investigations - which resulted from Andrew Gilligan's investigations in this newspaper - concerning the maladministration of more than £3 million of London Development Agency money, show exactly where this can lead.

As London's only paid-for newspaper, we considered it our responsibility to investigate the Mayor's record in detail. Over the past six months, we have uncovered and chronicled the flaws of his administration. We are proud that we have transformed what was anticipated as a one-sided romp into a hard-fought campaign which has electrified London and beyond. Alone, the Standard has exposed the sleaze and cronyism which we believe now surrounds the Mayor; Channel 4 and BBC London have followed. Our findings have helped persuade not just the Telegraph group and the Daily Mail to support Boris Johnson, but also The Sun and The Times, which have not backed the Conservative party at a major election since 1992.

But the reason for choosing Boris Johnson is not simply as the default alternative, or to give him a chance - the main reason why most national newspapers have endorsed him. More positively, Mr Johnson has the potential to succeed where Mr Livingstone has failed.

Mr Johnson has a vision for the governance of London which is genuinely attractive. He aspires to a tolerant and inclusive city - where power is devolved to localities and neighbourhoods. He seeks to encourage community groups, churches and voluntary bodies and to empower people on the ground in exercising authority. In this he is right - London needs not more power exercised from the centre but the rebuilding of society from the grassroots. He has no truck with attempts to divide the city by race or religion for political ends. He is not divisive in the way Mr Livingstone is, and indeed his rule is likely to be less overtly political.

Moreover, although he eschews grand plans, Mr Johnson has a vision for the physical fabric of the city - he wants new urban developments to be beautiful, not merely functional. He has clearly prioritised fighting crime, a major concern for all Londoners which Mr Livingstone has often downplayed. His approach to transport is common sense, phasing out bendy buses as well as scrapping the Mayor's planned £25 congestion charge for high-emission cars.

As an individual, Mr Johnson has considerable strengths. He has a better and broader mind than most contemporary politicians. He has political courage - as can be seen in taking the decision last summer to stand at a time when Mr Livingstone seemed unbeatable, something more senior Conservative colleagues shied away from. He may not have a reputation as a master of detail but during the campaign he has shown that he has steeped himself in the complexities of London government.

From a somewhat chaotic and slow start, he has developed into a committed and serious politician who can cope with the rigours of a testing campaign. Having a sense of humour should not deny you office, as Ken would testify. Crucially, he is a good delegator who will appoint people from the City and elsewhere in the private sector with real organisational strength and experience.

He has shown he can command loyalty. And while there is little doubt that he can build a strong team, he appears to have no desire to dispense with the genuine talent and expertise that does exist beyond political cliques at City Hall and in Transport for London.

Honesty and competence are the overriding issues in tomorrow's mayoral election. Democracy cannot properly function if our elected representatives have not proved themselves to be the guardians of integrity. Ken Livingstone has comprehensively failed that test. Londoners should vote for change and make Boris Johnson Mayor.

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