The mayor of London, Labour's Sadiq Khan, reckons his party will be the biggest in England, Scotland and Wales.

This, he tells the BBC, is remarkable given that he and Heidi Alexander - who has just won Swindon South from the Tories - "sat through 2019 when we were genuinely fearing our party was on the brink of extinction".

"In my wildest dreams, four and a half years ago did I think I'd be here? No," Khan says. "Keir [Starmer] did though and he deserves massive credit for getting us here."

Another swing of Conservative vote share in Reform's favour - although Reform's Ashton Muncaster isn't at the count to enjoy his second place, due to illness.

Rajini Vaidyanathan
Reporting from Welwyn Hatfield

Could Welwyn Hatfield deliver one of tonight’s "Portillo moments"?

Back in 1997, the sitting defence secretary lost his seat as Labour swept to victory in a landslide. Tonight, Defence Secretary Grant Shapps is predicted to lose his - with the exit poll giving him just a 6% chance of winning.

Sources close to Shapps say he's the "underdog but alive" - they're still holding some optimism, but they're also realistic, it's a big hill to climb.

Labour on other hand isn't giving anything away - except to say they’ve had a good polling day.

The exit poll places Reform UK in third place - the party says it's feeling positive. The counting continues in fervour - we’ll expect a result around 03:30 BST.

Professor Sir John Curtice
Polling expert

For Labour, the two-point rise in Blyth and Ashington and the seven-point rise in Houghton and Sunderland South is pretty much in line with what we were expecting from the exit poll.

The rise in Reform support, although quite substantial - up 13 and 18 points - is actually a little bit less than we were expecting and therefore conversely, the decline in Conservative support is rather less.

These are Labour seats - and therefore normally we wouldn’t be expecting the Conservative vote to fall that heavily.

But they are also heavily Leave areas, so we were anticipating Reform would put in a strong performance and push the Tory vote down more than in other Labour seats.

Martha Kearney
Reporting from Richmond and Northallerton

Here in the prime minister's Richmond and Northallerton constituency, local Conservatives are pretty confident. So Rishi Sunak's future as an MP may be secure - but what is going to happen to him?

Reliable sources say Sunak will stay on as Conservative leader to oversee a leadership contest.

Image source, PA Media

Alice Evans
Live reporter

Image source, Hulton Archive/Getty Images

If the exit poll, external is right, the Conservative Party will win just 131 seats tonight.

We've been sifting through some House of Commons Library data to try to compare that with previous Tory defeats.

The party's worst performance since 1900, in terms of seats, was in 1906 when 157 Tories were elected. To paint the picture, it was in the aftermath of the second Boer War, and the Liberals defeated an unpopular Conservative Party in a campaign focused on the cost of living.

Notably bad results since then include the 1997 general election, when 165 Conservative MPs were elected, which was a 30.7% share of the vote.

As we just reported, Labour's Heidi Alexander has won Swindon South.

In a victory speech, she says she's on a "mission to restore pride and opportunity to my home town".

"Together, we're going to put Swindon back on the map for all the right reasons."

Robert Buckland, a former Cabinet minister who has lost the seat, says the political system is at a "crossroads", and asks "do we value those who work to bring people together" or "shrug our shoulders and accept that politics is a mere circus".

"I believe with sincere and fierce conviction that my party has to make the right choice too," he says.

Professor Sir John Curtice
BBC polling expert

In the first Conservative-held seat to be declared tonight, we expected the Conservatives to lose 25 points, Labour to gain four and Reform gain 17.

In fact, the Conservatives lost 25 points, Labour gained eight and Reform gained 14.

This is just the kind of result that could be a sign of a serious Conservative decline in seats tonight.

David Bull, co-deputy leader of Reform UK, tells BBC Radio 4 that if the exit poll is right that Reform UK will gain 13 seats, then it is "an historic breakthrough for a party that is just four years old".

He says there are "shy Reform-ers" who don't want to admit to friends and family they are voting for the party, because they are "labelled in a very negative way".

"Thirteen seats shows the weight of support from people around this country," he adds.

Mr Bull and Labour peer Lord Mandelson clashed over public support for Reform UK.

Reform UK leader Nigel Farage says the two results in from the north-east of England - in which his party came second - shows his party is going to win "many, many seats".

In a video posted on social media, he claims his party has received a higher share of the vote in those "than any possible prediction or projection – it's almost unbelievable".

Image source, PA Media

Sharon Hodgson is re-elected for Labour as Reform beats the Tories to second place again.

Former justice secretary Robert Buckland has lost Swindon South to Labour's Heidi Alexander.

She won with 21,676 votes, Buckland came in second with 12,070.

He's the first Conservative to lose his seat tonight, having held the seat since 2010.

The result is expected soon in Swindon South - currently the seat of former Conservative minister Robert Buckland - and where Labour is already celebrating.

BBC reporter Julian Worricker is at the count and tells BBC Radio 4 and 5 Live that the Conservatives are expecting they will lose. Labour candidate Heidi Alexander walked into "rapturous applause" from her supporters, he adds.

He says Labour are "absolutely cock-a-hoop already".

"If Labour don't win Swindon South then the celebrations that I have just witnessed... will be highly embarrassing."

Andrea Leadsom, who was a minister in the Department of Health and Social Care under Rishi Sunak but stood down at this election, says the strong showing of Reform UK so far suggests "perhaps it's that we've not been conservative enough".

Asked if she can be certain that her party will not descend into civil war, she tells the BBC Tories recognise they'll have to regroup and rethink - adding "we will be very ruthless about it".

Image source, PA Media

Welsh Conservative Senedd leader Andrew RT Davies tells BBC Wales he's angry at Rishi Sunak's decision to hold a general election in July.

"I have no words that can describe my frustration at some points of the campaign," he says.

"No one really understood why we were sitting here tonight instead of the autumn", which he suggests would have given the Tories the "best possible chance".

Tories turn fury on Sunak's inner circlepublished at 00:09 British Summer Time 5 July

00:09 BST 5 July

Henry Zeffman
Chief political correspondent

As they wait for more results, some Conservatives are turning their fury on Rishi Sunak’s inner circle.

Shortly before polls closed, Sunak announced a string of honours for former cabinet ministers such as Theresa May and Chris Grayling.

He also gave a peerage to Liam Booth-Smith, his chief of staff, and a knighthood to Oliver Dowden, his deputy prime minister.

I’ve just had this through from a senior Conservative source:

"There is widespread disgust at the reward for abject failure in Rishi’s dissolution list. Sir Oliver Dowden pushed for an early election and has been the worst DPM in living memory, demonstrating terrible political judgment.

"Lord Booth Smith is the architect of the Sunak project and connived to bring down the biggest election winning Tory PM in a generation. Sunak’s pledge to bring integrity back to politics when he entered Downing Street has proven to be a total lie. This an utter disgrace."

That gives you a flavour of the recriminations which are beginning right now.

Sir Charles Walker, who stood down as a Conservative MP at the election, responded to that quote in our radio studio just now, saying: "The idea that people in the Conservative Party are going to be as sanguine and magnanimous as I am, is for the birds."

Conservative Jacob Rees-Mogg tells the BBC's election programme that he thinks the Conservatives "took its core vote for granted".

He says this is "why you see so many people who may have voted Conservative previously going off to Reform," he says.

"We have no divine right to votes," he adds.

He adds that changing the Conservative Party leader caused "issues" for them. The Tory Party has had three leaders since the 2019 general election.

Professor Sir John Curtice
BBC polling expert

It appears the SNP may have suffered a more substantial reverse in its fortunes than most polls anticipated.

The decline in the party’s support does, however, appear to be lower in places where a high proportion of people identify as Scottish rather than British.

The exit poll only has a small number of sampling points in Scotland. So the forecast for the SNP - and for Scotland in general, where the exit poll is pointing to substantial Labour gains - must be treated with a great deal of caution.

The next result is in - Labour's Lewis Atkinson has won Sunderland Central with 16,852 votes.

Once again, Reform beat the Tories to come in second place.

If the exit poll is correct then it will be a "very difficult night for the SNP", the party's deputy leader Kate Forbes has admitted.

"This has been a change election," she says, to bring an end to the Tories.

She adds that the SNP will now set out its "agenda to regain and rebuild the trust of voters across Scotland".