Jogging all the way to City Hall? Boris and wife get in training for office

Mr Johnson and his wife, Marina, went for a jog around their Islington home to pass the time as they waited for tonight's official declaration at City Hall tonight.

But the champagne was on ice at Mr Johnson's campaign headquarters and the result appeared a foregone conclusion.

With more than half the constituencies declared, City Hall sources suggested Mr Johnson had an insurmountable lead over Ken Livingstone on first-preference votes.

Mr Livingstone would need more than 90 per cent of second preferences to have a hope of catching up.

One senior Tory told the Standard this afternoon: "We are more and more confident - we think Boris might even win on first preferences alone."

To do so Mr Johnson would have to win more than 50 per cent of first votes.

Tory activists said there had been a particularly high turnout in heartlands such as Croydon, Sutton, Bromley and Bexley.

Reports from insiders at count centres at Olympia and Alexandra Palace suggested the race was tight even in some Labour strongholds.

One bookmaker announced it was already paying out on a Johnson victory.

Gordon Brown took on an almost valedictory tone when he congratulated Ken Livingstone on his record in power.

Deputy Labour leader Harriet Harman admitted London could not be insulated from the disasters hitting the party everywhere else in its worst local election results in 40 years.

"We expect the national situation to be reflected in London, probably," she said.

Mr Johnson was still trying to appear cautious as he went for his run.

"I wouldn't put my trust in Harriet Harman's judgment," he said. "I think the [Conservative] party has done fantastically well nationally but London is a different kettle of fish and we will just have to wait and see."

After spending the morning at home, Mr Johnson headed to his campaign headquarters to thank key members of his team.

He will join Mr Livingstone, Lib-Dem Brian Paddick and the seven other mayoral candidates for the official announcement at City Hall. Election insiders suggested turn-out would hit 45 per cent across the capital with more than two million people having voted.

The Mayor's aides said they had "fought the best campaign they could" and he would do better than Labour nationally.

Before the counts began, there were complaints at Excel centre that about 30 per cent, or 300, ballot boxes were open and could have been tampered with. Assembly candidates were waiting to discover if they had won one of 25 seats.

Lib-Dem insiders were down-beat about their prospects of taking a constituency while the Greens were said to be doing well London-wide, raising the prospect of them winning a third seat. The Greens also won Highgate from the Tories in a council ward by-election.