The big news about Boris Johnson's first anniversary is that his first anniversary is big news. Such accolades are normally reserved for presidents. Nothing in the campaign for direct election in Britain vindicates the cause as much as this fact. There is no democratic ­accountability without turnout, no ­turnout without publicity, and no publicity without personality. Direct election boosts them all. In 2008 Johnson's election added 10% to London's vote.

How many in Britain ever discussed the first years of Mike Whitby, Warren Bradley, Andrew Carter or Richard Leese? Who has heard of them, even if they live in Birmingham, Liverpool, Leeds or Manchester, which they happen to rule? Denying British cities the elixir of a democracy permitted to German, French or American ones is the establishment's way of suppressing innovation and dissent. It keeps power within the club. It is rubbish.

Johnson's first year in charge of the capital has refuted the ­malicious forecasts of his foes and ­tentatively confirmed those of his fans. London has not collapsed into a Billy Bunter comedy routine. The most incompetent central government of recent times, lauded by Johnson's enemies, has visited on ­London its most severe postwar crisis. The mayor has not panicked.

Johnson has had to remove a police chief who lost the confidence of his force and whom the home secretary lacked the guts to sack. He has honoured his pledges to end bendy buses, put more police into public transport and ban alcohol on the tube. He cycles every­where, while wrestling with a tube system brought to the brink of bankruptcy by Gordon Brown's privatisation. He must now face an economic storm by rebuilding the capital's economy on something other than speculative froth.

Given the collapse of London's biggest industry – finance – Johnson has promoted other industries, notably higher education, health and tourism. He has been less than courageous in trying to curb the lunatic extravagance of Tessa Jowell's super-Olympics. Her vast budget simply swamped him. He also failed, on day one, to kill off Crossrail and divert its resources to ­restore the tube's physical and emotional health, now approaching financial meltdown.

The mayor's early U-turn on tall buildings showed a man susceptible to the power of money, proving that Tories capitulate to rich architects/developers as easily as socialists. The threatened skyscrapers over the South Bank and Waterloo, like those over Ealing and Battersea, should be dubbed, if built, Boris's babes. They will be his symbols long after he has gone. These are the sort of big government decisions that Johnson has yet to show he can grasp.

Yet Johnson has done much to surprise the sceptics. His forthcoming conference on "a new London vernacular architecture" indicates sensitivity to the city's environment rare in a city politician. Perhaps the eye of a cyclist makes him alert to the quality of London streetscape, in contrast to Livingstone's infatuation with the Foster/Rogers cosmopolitan school of "icons in deserts".

There is also a real possibility of London getting some version of the Monderman "shared streets" policy – everywhere on the continent but unknown in the overengineered streets of Britain. Already Johnson is planning to reduce the number of lights, signs, furniture and general clutter, and to end many unnecessary one-way streets. He claims that pedestrians and cyclists should ­dictate the movement of motor ­vehicles, not the other way round, and that this actually aids traffic flow.

Nor has Johnson ignored the city's political dynamic. In a remarkable deal negotiated this week, he declared an intention to tear up the existing relationship between tiers of government in the capital. He wants the 32 boroughs to appoint their own police commanders and assume control over doctors' surgeries and primary care budgets. He is also handing over local bus routing and the regulation of trunk roads.

This could be bloody in the short term. But nothing is more likely to ­galvanise borough government, ­possibly at the expense of mayoral power. Since much of it will require central ­government approval, it will also need Johnson to mobilise the full force of his direct mandate.

Devolving democratic accountability for the frontline health service and for neighbourhood policing will take courage and a readiness to risk mistakes. It is hardly new. Most of Europe practises it, to general consumer satisfaction. But in Britain it is a true democratic breakthrough, a decentralisation that has eluded both Labour's pseudo-localists and David Cameron's lukewarm devolution. Since the mayor may need Cameron's permission, he is putting his former boss firmly on the spot.

Johnson has changed the style and language of politics. His tendency to make every topic a joke, often at his own expense, was regarded as an engaging liability. It had appeal outside the charmed circle of political literates, but was predicted to have a short lifespan. How could you have a mayor who said gosh, crumbs and crikey; who claimed to have "played God at 10"; who wants a "grand smashing of PlayStations"; and who professed to identify with the Incredible Hulk, since "the madder Hulk gets the stronger Hulk gets"?

The novelty has endured. As last year's campaign showed, the public likes leaders who speak their minds. However distant from ordinary Londoners Johnson's patrician personality might seem, it has come across as genuine, unchained by spin and correctness. What makes him a celebrity, particularly among the young, was not what he says but how he says it. His artless gaffes have the freshness of sincerity, with none of the humourless artifice of the Westminster village. Johnson can get away with littering his language with Athens, Pericles, Thucydides and Cicero, because it is done naturally. Authenticity of any sort is rare today.

A poll this week in the London Evening Standard indicated that Johnson would now trounce his former opponent, Ken Livingstone, winning a remarkable 49% of those polled. This is testament enough to his popularity. Almost all leaders lose traction in their first year.

Yet an intriguing finding is that Alan Sugar, the newly touted ­television tycoon, might beat Johnson by 40 points to 32. The implication is that, in civic politics, to be "outside the tent" is a real asset, the further the better. Both Livingstone and Johnson traded on this factor to win their first elections. But Johnson still suffers in the poll as a card-carrying Tory.

Sugar combines recognisability and independence with an image of not suffering fools gladly. Like Johnson he speaks his mind and does not care whom he offends. He is ambitious and has the party credentials to be well placed as the next, possibly Labour, ­candidate for mayor.

This does not mean Sugar will stay the course. That he is even in consideration shows how far London politics has moved since direct election transformed darkness into light, how far it has come since leftwing militants could seize power in County Hall in their 1981 corridor coup. Any Londoner can now think himself Dick Whittington without needing to belong to a political club.

simon.jenkins@theguardian.com