Can loose cannon be trusted in office?

Boris Johnson’s triumph has turned the tables on critics who claimed he was too much of a loose cannon to hold senior office.

When he was picked as Conservative candidate for the mayoral race last year, many believed the gaffe-prone Old Etonian would be unable to make it to polling day without self-destructing.

He was branded a “clown” and a “joke” by his main rivals, and the media was often more fascinated by his chequered past, his colourful turn of phrase and his shock of blond hair than by his policy platform for the capital.

But he now has the largest personal mandate of any UK politician and has more power in his hands than any other Conservative in the UK.

Under the close eye of Australian polling guru Lynton Crosby, Johnson’s campaign was far more disciplined than many had expected.

There were the occasional gaffes - he told an Asian radio DJ not to try to “out-ethnic” him - and his opponents complained that he ducked out of difficult hustings. But for the most part, Mr Johnson stuck doggedly to his policy script.

The big question now is whether, without the discipline of the mayoral campaign and the restraining hand of Mr Crosby, he will be able to avoid going back to his old ways.

With the £16 billion Crossrail project and the preparations for the 2012 Olympics to oversee, there are certainly opportunities galore for mishaps for a man whose administrative experience is so far limited to watching over a couple of dozen journalists as editor of The Spectator.

Even before he was picked as mayoral candidate last September, Mr Johnson’s newspaper columns and appearances on the TV show Have I Got News For You had already made him one of the UK’s most recognisable political figures.

But the 43-year-old’s high profile was achieved at a price, with bad publicity over rumours of affairs and a series of gaffes. He was forced to apologise to Liverpool after allowing The Spectator to accuse the city of “wallowing in victim status” in the wake of the murder of Ken Bigley and also said sorry to Papua New Guinea after linking it with “cannibalism and chief-killing”.

Born Alexander Boris de Pfeffel Johnson, he was educated at Eton and Oxford. Twice-married, he has two sons and two daughters.

He was sacked from his first job as a journalist for making up a quote, but later made a name for himself as Daily Telegraph’s correspondent at the European Commission.

He was fired from his first frontbench job by former boss Michael Howard for denying an extra-marital affair.

Despite widespread expectations of a farcical campaign, Labour’s Ken Livingstone never underestimated the threat, describing Mr Johnson as “the most formidable opponent I will face in my political career”. How right he was.