Preliminary results from the election count suggest Boris Johnson is leading the race to become London Mayor.

With just over one-fifth of ballots counted in the 14 electoral areas, Mr Johnson is ahead in nine while Ken Livingstone leads in five, according to the BBC.

The results are expected to be announced at 8.30pm this evening.

Bookmakers Paddy Power have already paid out on a Boris Johnson victory.

A spokesman said: "We thought: why wait? With Labour being killed up and down the country and the betting on Boris 48 hours before the election being a one-man show, we thought punters would want to get their money early."

The race to run City Hall is the highest-profile contest in the 2008 round of elections, and its result could have a powerful impact on national politics in the run-up to the next general election.

Victory for Mr Johnson would add considerable momentum to Tory leader David Cameron's drive to win power nationally, and would make the former journalist the most powerful Conservative in Britain.

But if Mr Livingstone sees off the Tory challenge, it will provide a crumb of comfort to a bruised Gordon Brown after his pummelling in the local elections.