Michael Howard conceded yesterday that the Conservatives are lagging behind in the election campaign.

The Conservative leader used a football metaphor to try to persuade his troops that they can overhaul Labour by May 5.

Speaking to ITV, Howard said: "You often find if you are a football fan there is a team that might be two goals down at half-time, they win the game.

"I went to the Carling Cup final a few weeks back to watch my team Liverpool play Chelsea.

"We were ahead until the last 10 minutes and then we were screwed. So the election is not over until May 5 and I am confident we can win that."

Tony Blair delivered a similar message. Campaigning in Bristol with Gordon Brown, the prime minister warned his supporters against complacency.

"Never mind what the opinion polls say, the thing that counts is going to be in constituencies, often marginal constituencies, where a few hundred votes or a few thousand either way can decide the course of this election. The only way of getting a Labour government on May 6 is to vote for it on May 5."

However, the Times points out that despite Howard's claim that teams trailing 2-0 at half-time "often" come back to win the game, the statistics do not match his assertion.

Of 214 occasions where one team was leading 2-0 at half-time, only five times did the side losing recover to win.

In other words, by Howard's criterion, the Conservatives have a 2.3 per cent chance of taking power.