Voters across the UK thronged polling booths Thursday to elect their next government, with most analysts and opinion polls predicting a third term for the Labour Party led by Tony Blair.
Local elections in 34 county councils, three unitary authorities and four mayoral contests are also being held simultaneously.
Results are expected to start trickling in after polling ends late Thursday, with final results by Friday afternoon.
Under the winner-takes-all electoral system, 646 regional constituencies each elect one member of parliament.
In the last Parliament, Labour had 410 MPs, the Conservatives 164 and the Liberal Democrats 54.
Four newspaper polls on Thursday gave Blair's Labour a lead of between three and six points over the main opposition Conservative Party. But surveys also indicate that Labour supporters are less likely to vote, in which case the key marginal constituencies will determine the end result, and the Labour victory margin could be a lot smaller.
The nationwide turnout in 1997, which brought Blair to power, was 71 percent. But in in 2001, that dropped drastically to 59 percent in 2001-- the lowest level since World War One.
If Blair--who celebrates his 52nd birthday Friday-- wins, he would be the first Labour leader to win three successive elections.
Though he has pledged to serve a full third term and not seek a fourth, some analysts say he may hand over power to Chancellor Gordon Brown halfway through his third term.