By then the result was clear -- Blair's Labour Party had won the election, but with a much smaller majority.
"It seems as if it's clear, that also that the British people wanted a return of the Labour government, but with a reduced majority. And we have to respond to that sensibly, and wisely, and responsibly. We have to make sure that we focus on the things that matter to people, the things that they've talked about to me during the course of this campaign," Blair said.
A somber Blair acknowledged the impact on voters of his unpopular decision to go to war in Iraq.
"I know, too, that Iraq has been a divisive issue in this country, but I hope now that we can unite again and look to the future, there [in Iraq] and here [in Britain]," Blair said.
Blair lost at least one MP, Oona King, solely because of the Iraq war. She lost to George Galloway, a former Labour rebel, in a London constituency with a large Muslim population.
Galloway had this message for Blair:
"Mr. Blair, this is for Iraq. This defeat that you have suffered and all the other defeats that New Labour has suffered this evening are for Iraq. All the people you have killed, all the lies you told have come back to haunt you. And the best thing the Labour Party could do is sack you tomorrow morning as soon as they get back to work," Galloway said.
With most of the 645 constituencies counted, polls are forecasting a Labour majority of between 60 and 80 seats. That's well below the 161-seat majority Labour won last time.
The leader of the main opposition Conservatives, Michael Howard, conceded defeat, but said his party had made important gains.
"For the Conservative Party, I think that what has happened on this election day marks a significant step towards our recovery. I am proud of the campaign that we have fought," Howard said.
And there was consolation, too, for the third party, the Liberal Democrats, who captured some seats from both Labour and the Conservatives.
"The era of three-party politics right across the United Kingdom is now with us," said Charles Kennedy, the party leader.
This victory is a historic one for Labour and for Blair. But already there are warnings of difficult times ahead.
Analysts say a smaller majority will make it harder for Blair to push through his policies, especially since some of his own Labour MPs are still angry over the Iraq war.
But some see an even greater danger ahead -- that Blair himself could be replaced sooner rather than later.
The clear favorite to take over before the next election is Chancellor of the Exchequer (Finance Minister) Gordon Brown.