BREAKING NEWS: Britain's Election 2015: Exit poll puts Tories close to majority

An election exit poll is a poll of voters taken immediately after they have exited the polling stations. Unlike an opinion poll, which asks whom the voter plans to vote for or some similar formulation, an exit poll asks whom the voter actually voted for.

The Conservatives are set to be the largest party in the Commons but just short of a majority, according to the general election exit poll.

The survey taken at polling stations across the UK suggests the Tories will get 316 MPs to Labour's 239 when all the results have been counted.

It suggests the Lib Dems will get 10 MPs, the SNP 58, Plaid Cymru 4, UKIP 2 and the Greens two.

The exit poll was conducted by NOP/MORI for the BBC, ITV and Sky.

The first election results are due before midnight with the final result on Friday afternoon.

The finishing line needed to form a majority is 326.

If the exit poll is accurate, as it was in 2010, David Cameron could be on course to remain prime minister as the head of a minority government without the need for a coalition - although he might have to rely on the support of the DUP or the Lib Dems.

Even if Labour leader Ed Milband was able to persuade the Lib Dems to join the SNP in backing a Labour government, he would not have the necessary numbers to get his legislative programme through Parliament in a Queen's Speech.

Labour looks set to suffer a hammering in Scotland at the hands of the SNP, with their vote dropping an average of 18%.

But the exit poll suggests it will be an even worse night for the Lib Dems, with the party's vote falling 16% on their 2010 share - worse than the most gloomy predictions before polling day.

Lib Dem election chief Lord Ashdown told the BBC: "If this exit poll is right I will publicly eat my hat."

SNP leader Nicola Sturgeon was also cautious about the exit poll.

She tweeted: "I'd treat the exit poll with HUGE caution. I'm hoping for a good night but I think 58 seats is unlikely!"

Pollsters interviewed 22,000 people in 141 polling locations in 133 constituencies throughout Great Britain.

A total of 650 Westminster MPs will be elected, with about 50 million people registered to vote.

There are also more than 9,000 council seats being contested across 279 English local authorities.

Mayors will also be elected in Bedford, Copeland, Leicester, Mansfield, Middlesbrough and Torbay.

Some votes had been cast before Thursday through postal voting, which accounted for 15% of the total electorate at the 2010 general election, when the overall turnout was 65%.