London: London's new mayor, an eccentric Conservative lawmaker, was sworn in on Saturday  after ousting the left-wing incumbent in a vote that capped the worst local election results for Prime Minister Gordon Brown's party in four decades.

With a clump of unruly blond hair sticking up during his victory speech after midnight, 43-year-old idiosyncratic ex-magazine editor Boris Johnson said his triumph over Ken Livingstone offered a glimpse of Britain's likely political future.

The result - Johnson polled 1,168,738 to Livingstone's 1,028,966 - capped a disastrous performance for Brown's governing Labour in their first electoral test since he assumed power when Tony Blair quit last June.

In a brief speech, Johnson reiterated promises to tackle knife crime, improving the bus system and increasing affordable housing, but said he may not be able to stop his trademark slip-ups.

"I was elected as new Boris and I will govern as new Boris, or whatever the phrase is," he told the BBC, paraphrasing Tony Blair's speech after taking the Labour Party to a general election victory in 1997.