Image source, Reuters

Ballot boxes have arrived at counting centres across the UK as counting gets underway.

Pictured below are ballots being tallied in Sunderland, Uxbridge, Chesterfield and Hartlepool.

Sunderland always like to be first - will they manage it this time? If so, we should get their result around 23:00.

Image source, Reuters

Image source, Reuters

Image source, Reuters

BBC Radio 4

Nipping back to Radio 4 for a minute for some more reaction from party big hitters.

Shadow international trade secretary Barry Gardiner says if the exit poll proves to be accurate, "it's a devastating result".

"I don't feel it so much for the Labour Party as for all the people in the country who were depending upon a Labour victory - who felt that that offered them hope," he adds.

"For them I feel huge huge sorrow."

Mr Gardiner puts the predicted defeat down to the same thing as his colleague John McDonnell - blaming Brexit for drowning out everything else.

Foreign Secretary Dominic Raab isn't celebrating just yet - again like his colleague Priti Patel.

"We'll wait for the result but it feels like that positive message, and the need to end the uncertainty, has won through - which is good news," he says.

There's been a bit of a tussle for Mr Raab in his own seat against Liberal Democrat contender and first-time candidate Monica Harding.

Despite the closely-fought race he may have on his hands, Mr Raab says he feels "upbeat".

Faisal Islam
BBC Economics Editor

The pound has been a bit tentative during the day as various rumours were going around.

But immediately when the exit poll was announced, it was up, up, up and away.

The prediction of a smaller majority may have left Boris Johnson at behest of factions in his party.

But this gives the PM room for manouvre to get things through the Commons.

The most disruptive form of a no-deal Brexit was taken off the table with Boris Johnson getting some form of deal.

That is why the markets seem to be showing cheer.

But it may be different as some more results come through.

BBC Newsbeat

Image source, PA

Earlier this week, former leader of the Scottish Conservatives Ruth Davidson promised to swim naked in Loch Ness if the SNP got 50 seats.

The exit poll has the SNP on 55 seats... so if the prediction is proved correct it might be time for Ms Davidson to reach for the goose fat.

However, as our correspondent Nick Eardley pointed out we need to be cautious about the situation in Scotland because so many Scottish seats are marginal.

A bit more from John McDonnell. He's asked if the Labour Party will need to return to the "centre Left", rather than Jeremy Corbyn's socialist direction - to that Mr McDonnell insists his party already is "centre Left" under Mr Corbyn.

"I hate to use this expression but maybe [voters] did just want to get [Brexit] done," he says.

"But I am not sure Brexit will be done as a result of this."

Mr McDonnell says people have been "almost in despair" and "had enough of what has been going on with a failure of successive Conservative prime ministers".

But he adds: "The disappointment they will find is Brexit isn't going to go away and negotiations will be going on for a long time."

Nick Eardley
Political correspondent

If this exit poll proves to be correct it will see the Tories' dreams comes true and Labour’s nightmare play out.

The numbers would give the Conservatives their biggest majority since Margaret Thatcher was PM and leave them considerable room to do what they want in Parliament.

Labour would be shattered. Not since the 1930s have they failed to win 200 seats.

The SNP’s result would be extraordinary too, just shy of their best ever in 2016.

My sources in Scotland are applying plenty of caution at the moment because so many Scottish seats are marginal - but anything close to it will throw the independence question back front and centre in Scotland.

Shadow chancellor John McDonnell gives us the first reaction from a Labour figure. He says if the result is anywhere near the exit poll it "will be extremely disappointing for the party overall and the movement".

He admits it has "come as a shock" and he "thought it would be closer".

Mr McDonnell says: "We knew it would be tough because Brexit has dominated."

But he adds he hoped "other issues would cut through".

He is pressed on whether he and Jeremy Corbyn will resign, but he says: "We will see the results in the morning and decisions will be made then."

If the exit poll is correct - and it is just a prediction after all - Labour is set for a very bad night.

And that opens up a whole host of other questions - first and foremost, what happens to the party next?

Here's the moment when the BBC's Huw Edwards announced the exit poll resulting, suggesting Boris Johnson is on course for a majority.

Read our full story on the unfolding events here.

Home Secretary Priti Patel is the first politician to react in the BBC News election special.

She says it is important "to recognise this is a projection not an actual result".

But she praises "amazing candidates" taking out the Tory message that "we need to break the gridlock that has dominated Parliament and get Brexit done."

Ms Patel says the first priority of the government, if the poll proves to be correct, is to get on with Brexit and move the country forward onto people's other priorities.

She won't be drawn on whether a Conservative government would bring back the Brexit bill to Parliament before Christmas, but she says they will "move quickly".

Jeremy Vine
Presenter, BBC Radio 2

To win an overall majority in the House of Commons you need 326 seats.

Theresa May fell short in 2017, but the exit poll has Boris Johnson going straight through that 326 figure making a gain of 50 seats.

The other stand-out is just how badly Labour's showing is in the exit poll.

If they do get 191 seats it would be below what Michael Foot did in 1983.

And then there is this amazing result by the SNP - if the exit poll is correct.

This would end that period in Parliament when no-one could get anything done.

If that is what happens it would be a a stunning victory for the Conservatives.

BBC Radio 4

There are various ways to follow the results tonight. Here with us, of course. On the BBC News Channel, and over on BBC Radio 4 (and later 5 Live)

Prof Philip Cowley, from Queen Mary University, with be on the radio with Emma Barnett and James Naughtie throughout the night to help make sense of the results.

He says if the exit poll is correct, it would be Labour's worst result since 1935, and the best Conservative result in seats since 1987.

He says it would be a "really impressive" result that's "right at the top end of Conservative expectations".

Laura Kuenssberg
BBC political editor

There has been an overriding sense that this was an almost impossible election to read.

And while the Conservatives hoped it was possible to make in-roads in Leave areas, it wasn't a done deal.

Although lots of issues have been discussed and have mattered, this has broadly been a Brexit election.

Remember, though, we won't know the final numbers until the end of the night.

Laura Kuenssberg
BBC political editor

If these figures are broadly correct Boris Johnson may just have redrawn the map.

With these figures he would have clear backing from the green benches behind him to take us out of the EU next month.

It would also mean another five years of Conservative rule with a solid majority behind him.

We are also seeing Labour going down to a fourth election defeat in a row - a serious and historic loss.

The SNP appears to have increased their dominance in Scotland.

The other parties do not appear to have made a breakthrough.

But these are early days. And it is still only a prediction.

Professor Sir John Curtice
Polling expert

The variation in the ups and downs in the parties' shares of the vote reflects differences in how constituencies voted in the 2016 referendum.

The Conservatives are expected to advance most strongly and Labour fall back most in areas that voted most strongly for Leave - many of them more working class seats.

In contrast, the Conservative share of the vote is expected to fall back on 2017 in those areas that voted most strongly for Remain, while Labour’s vote is expected to fall back rather less.

However, even in the most strongly pro-Remain seats there could still be a small swing from Labour to the Conservatives.

One consequence of this pattern is that the Conservative share of the vote is expected to fall back slightly both in London and in Scotland, and do little more than replicate the 2017 vote in the South East outside of London.

The party will advance most strongly in the Midlands and the North of England.

The pattern of Labour performance is largely the obverse of the Conservative Party, with the party’s votes falling most heavily in the North and Midlands.

The Liberal Democrats appear to be headed for a disappointing night. Although the party is expected to advance a little more in those seats that voted heavily Remain – typically seats with graduates - but this is not expected to bring the party much benefit.

The SNP are expected to advance strongly in Scotland and could well take seats from all three of their Unionist rivals.

Conservatives 368 (+50)

Labour 191 (-71)

Lib Dem 13 (+1)

SNP 55 (+20)

Plaid Cymru 3 (-1)

Green 1 (no change)

Brexit Party (no change)

Other 19 (+1)