The exit poll suggests the Conservatives will be the largest party with 314 seats, a loss of 17 seats, with Labour on 266, a gain of 34.
It also put the SNP on 34, the Lib Dems on 14, Plaid Cymru on three and the Greens on one.
Live blog begins below the video
Exit Poll predicts hung parliament
UK Election Day 2017
Politicians, voters, and even their pets have been heading to polling stations and are posing for the cameras at every opportunity.
In her final message on Thursday, the Prime Minister plead with voters to back her in the Brexit negotiations, adding: “If we get Brexit right, we can build a Britain that is more prosperous and more secure. A Britain in which prosperity and opportunity is shared by all. A Britain where it’s not where you come from or who your parents are that matter, but the talent you have and how hard you are prepared to work. The greatest meritocracy in the world.”
In a message directly aimed at wavering voters who may lean towards other parties, she added: “I can only build that better country and get the right deal in Brussels with the support of the British people. So whoever you have voted for in the past, if that is the future you want then vote Conservative today and we can all go forward together.”
The Labour leader, who claims to have addressed more than 100,000 people at campaign events, used a speech at his final rally in his north London stronghold to claim he had reshaped British politics.
He said: “As we prepare for government, we have already changed the debate and given people hope. Hope that it doesn’t have to be like this; that inequality can be tackled; that austerity can be ended; that you can stand up to the elites and the cynics.
“This is the new centre ground. The place where most people actually are. The policies the majority actually want, not what the establishment and its media mouthpieces insist they should want. This is the new mainstream, and we have staked it out and made it our own – together.”
Liberal Democrat leader Tim Farron urged Labour supporters to vote tactically to keep out the Conservatives.
He said: “We will stand up for you on Europe, on schools and hospitals and to stop the heartless dementia tax. So stand up and make your vote count for the Liberal Democrats today.”