LONDON – Divided over the country’s ballooning debt, the economy and the contentious issue of immigration, the three front-runners in Britain’s general election can still agree on one thing: This race is anyone’s to win.

Conservative challenger David Cameron, fresh off what observers said was his best live televised debate performance to date, told BBC radio that next week’s national election was “still far from won.”

Nick Clegg, riding higher in the polls than most political observers had ever expected, said the campaign was “wide open.”

Even Britain’s ever-optimistic former Prime Minister Tony Blair, who hit the campaign trail Friday in support of his successor, Gordon Brown, could only say that their governing Labour Party “has every chance of succeeding.”

An ICM/Populus poll, published Friday by The Guardian, showed the gap between each party within the margin of error. Statistically, the three-way contest involving Cameron, Clegg and Brown has become a dead heat.

Those figures are disappointing for Cameron, whose Tories at one point enjoyed a double-digit lead over Labour, which has run the country since Blair was elected in 1997.

But Labour managed to whittle away Cameron’s advantage as the election drew closer, and both parties have been caught off-guard by Clegg, whose affable and straightforward style in the nation’s first U.S.-style TV debate April 15 led to a surge in support for his opposition Liberal Democrats.

Andrew Gamble, the head of the department of politics at Cambridge University, said Cameron “should be winning this election by a mile.”

“The fact that they’re not is deeply troubling for the Conservatives,” he said. “Clegg is spoiling the party for them.”

Labour had bad luck Friday, when a car crashed into a bus shelter as the prime minister and several members of his Cabinet launched a new poster campaign nearby. No one was hurt in the incident, but evening TV newscasts captured Brown deputy Peter Mandelson’s speech briefly interrupted by a loud screech followed by the sound of a crash.

Pressed by a journalist, Mandelson denied that the incident was a metaphor for Labour’s election campaign.

Labour got even worse news when The Guardian newspaper announced its support for the Liberal Democrats and The Times of London backed the Tories.

The right-leaning Times’ endorsement of the Conservatives was no surprise, but Labour’s loss of the left-leaning Guardian was more damaging.

Still, with the election on May 6, Brown’s opponents aren’t taking anything for granted.

Addressing a crowd in northern England, Clegg said he was “certainly not going to rest one millisecond, one minute until this campaign ends — right up to the moment when people decide how to vote.”

“There are lots of people who haven’t decided how they are going to vote,” he said. “I think many people now see this campaign is wide open.”

In his interview Friday, Cameron said his party would “have to fight for every vote and every seat.”

Brown, too, has pledged to take his fight down to the wire.

“The time for debates is finished, the time for decision has begun,” he told supporters.

Gamble suggested that those very last seconds could still be crucial.

“In this last week, a lot of voters will be making up their minds,” he said.