Voters have been deciding the fate of thousands of would-be MPs as they cast their votes in the general election.
Voting is taking place in 46,000 polling stations
Tony Blair was among a steady trickle of people casting their votes in the Durham village of Trimdon Colliery.
Lib Dem leader Charles Kennedy and Michael Howard voted in their respective constituencies, after the punishing 30-day election campaign.
Polls close at 2200 BST, with the first results due about 2300. The winner will not be clear until early on Friday.
Electors will choose MPs in 645 constituencies.
The election has been postponed in the 646th constituency, Staffordshire South, because one of the candidates died.
Local elections are also taking place in 34 county councils and three unitary authorities in England. There are also four mayoral contests.
There are also elections in all 26 councils in Northern Ireland.
Labour leader Mr Blair cast his vote, along with his wife Cherie and two sons Euan and Nicky, at the Trimdon Colliery Community Centre in his Sedgefield constituency.
Mr Kennedy and his wife Sarah cast their votes at the Caol Community Centre in Fort William in his Ross and Skye constituency.
Conservative leader Michael Howard and his wife Sandra voted, along with their daughter Larissa, at a village hall in Hythe .
At the end of the last Parliament, Labour had 410 MPs, the Conservatives 164 and the Liberal Democrats 54.
The Scottish National Party also have five seats, Plaid Cymru four, the Democratic Unionists seven, the Ulster Unionists five, Sinn Fein four, the SDLP three, and one each for Respect, Independent and Independent Kidderminster Hospital and Health Concern.
To gain a majority at this election, when boundary changes mean there are fewer seats available, one party needs to win 324 seats.
Sunderland South was the first to declare its result in 2001, just 43 minutes after the polls closed.
But the national picture of how the parties stand will not emerge until at least 0100 BST on Friday.
Election organisers hope postal voting will help turn-out, although there have been concerns about the security of the system against fraud.
Voters taking the traditional polling station route are asked to take their voting cards to help officials, although it is not compulsory.
People who have been sent postal ballots can still vote by delivering them by hand to a local polling station or the address on their envelope.
Attention will also be focused on turn-out, which in 2001 fell to 59%, the lowest level since 1918. But with many people expected to vote after work there are no indications on turn-out levels as yet.
Previous elections suggest weather may have an impact on the numbers voting.
Cloud and patchy rain has been seen across much of the country, but it has been mostly dry in southern England.
In 1992, turnout was 78% on a generally dry and sunny day. Turnout was 71% in 1997, when again it was dry, sunny and very warm.
In 2001, the weather was very cool, with a brisk wind and blustery showers across the UK.