First Minister Carwyn Jones has said Labour leader Jeremy Corbyn had run a "superb" election campaign.

Mr Jones declined to mention Mr Corbyn once at the launch of the Welsh Labour campaign last month, and Welsh Labour ran a distinct campaign with Mr Jones at the centre.

Mr Jones told BBC Wales: "I am going to congratulate Jeremy Corbyn because I think he has run a superb campaign. He has been energetic, he has spoken to members of the public, he didn't just speak to meetings of people who were exactly like him.

"He took part in leadership debates, he listened to people, and that was the difference in this campaign, a Labour leadership in Wales and Britain that listened and a Conservative leadership in Wales and Britain that took people for granted and thought they didn't have to listen to people."

A Plaid Cymru source has played down the chance of any possible gains tonight.

The party is defending three seats, and was focusing efforts on making inroads in Ceredigion, Ynys Mon, Rhondda and Blaenau Gwent.

The source added that the party is expecting to feel the effect of the "two party squeeze," suggesting that a growth in support for the Tories and Labour will squeeze out Plaid as a smaller party.

The suggestion would be in line with the exit poll, which has Plaid on three seats - the same number they held at the 2015 general election.

Welsh Labour appear to be feeling optimistic following the publication of the exit poll.

AM for Alyn and Deeside Carl Sargeant said he felt "encouraged" by the prediction.

He said Labour had fought a "very hard campaign" in Wales.

Prof Roger Scully, of Cardiff University's Wales Governance Centre, says the exit poll prediction that the Conservatives will be short of an overall majority would be an "extraordinary outcome".

UKIP kept its deposits in all 40 Welsh seats in the 2015 general election, and since then won 7 seats in the 2016 Welsh assembly election.

However, the party’s popularity seems to be on the wane in Wales – UKIP failed to get a single councillor elected here in last month’s local elections, and a fifth of Welsh constituencies have no UKIP candidate this time.

Prof Roger Scully from Cardiff University’s Wales Governance centre predicted that the Conservatives would be the main beneficiaries of an UKIP ‘collapse’.

Jac Larner
Cardiff University

The issue of voter turnout - how many people eligible to cast a vote actually do so - has perhaps been more central to this general election campaign than any of the last two decades

The basic issue is this: higher turnout has historically tended to help the Labour Party, whereas a lower voter turnout has benefited the Conservative Party.

Throughout this election, polls have differed considerably in the vote shares they award the parties, but one constant has been the considerable age difference between the supporters of the two main UK-wide parties.

Labour has a considerable majority among voters under 30, the Conservatives are ahead among those over 55.

The big question for Labour this election is whether its young supporters have turned out to vote in large numbers. If they have, and it's a big if, they may be able to surprise the Conservatives.

Counting has begun in Aberconwy - a seat won by the Conservatives' Guto Bebb in 2015.

The exit poll predicts that the Conservatives will be the largest party.

So what does it all mean?

Arwyn's here with his election night box of tricks.

Jac Larner
Cardiff University

In 1992 and 2015 the exit poll underestimated the Conservatives' seat share, yet every post-1992 exit poll has predicted the largest party’s seat share within 15 seats.

For the smaller parties such as Plaid Cymru in Wales, it’s much harder for them to give an accurate prediction to due to smaller sample sizes.

We’ll have to wait for results to have a better idea.

And could this mean another election?

Mark Williams was the only Liberal Democrat MP elected in Wales at the last election. He has since become the party’s Welsh leader.

In 2015, the party lost ground across Britain but did worse in Wales where it lost two of its three seats, and its deposits in three-quarters of the Welsh constituencies.

Since then, the party was reduced to a single seat in the Welsh assembly in 2016, and Wales lost 11 Liberal Democrat councillors in last month’s local elections

Mr Williams will be hoping for signs of recovery tonight.

Nye Davies from Cardiff University's Wales Governance Centre says unless the party can make a comeback in this election, it might be a long time before it regains its pre-2010 heights.

Speaking after the exit poll was published, Welsh Conservative leader Andrew RT Davies said: "I have every confidence in Theresa May.

"We're at the start of the evening, we need to be working through these results, and there's a lot of time to pass now before we see what the final outcome is."

BBC Wales reporter Caroline Evans is at the Torfaen count where the returning officer says counting will be delayed because of the number of people bringing postal votes into polling stations today.

It seems that this time many more people than usual have decided to do so.

Plaid Cymru won three seats in the 2015 general election – the same number as it won in 2010. The party has never held more than four seats at Westminster, so any gains tonight would equal its best ever performance.

As Nye Davies explains, the party has tended to do better in assembly elections.

This is Plaid’s second UK General Election with Leanne Wood at the helm, and the party will be hoping the increased UK-level media exposure that comes during the campaign - Ms Wood has appeared on several live TV debates – will lead to an improved perfomance at the ballot box.

The party will also be hoping for an improvement in its overall share of the vote on 2015, when it scored 12.1% and was beaten into fourth place by UKIP.

David Deans
Wales politics reporter

Parties spend the first few hours of any election night briefing the media on their thoughts before results start to flood in.Welsh Labour have gotten in first. A source at the party claimed that the UK-wide exit poll is "extremely difficult to extrapolate to Wales, but shows the scale of the challenge Welsh Labour faced in this campaign". ·

The source said: "But the political weather remains extremely difficult, and retaining all our Westminster seats remains a challenge."

"We remain confident that our campaign, showing the positive change delivered by a strong team of Welsh Labour MPs working with a Welsh Labour government, will return a strong team of Welsh Labour MPs to Westminster."

Parties have been "complicit in confusion" in Wales by making campaign promises about devolved issues, a leading political expert has said.

Prof Laura McAllister, of Cardiff University's Wales Governance Centre, said voters had been left confused ahead of polling day for the general election.

Speaking earlier, she said every party had made pledges on devolved issues, such as health and education, which are "not up for grabs" in this election.

Labour has come first in Wales in every general election since 1922.

Although its dominance has been on the wane, the party’s vote share in Wales was 36.9% at the 2015 general election, up 0.7 of a percentage point since 2010

Labour won 26 of the 40 Welsh seats in 2015 having lost Gower and the Vale of Clwyd to the Conservatives, but winning Cardiff Central from the Lib Dems.

Nye Davies from Cardiff University’s Wales Governance Centre assessed the party's campaign last month.

Writing before the Manchester and London terrorist attacks, he considers how effective attempts to make a distinction between "Welsh" Labour and Jeremy Corbyn's Labour might be.

Jac Larner
Cardiff University

Just like two years ago, the exit poll has served up something of a surprise.

However, unlike 2015, this result is not out of the blue.

In the last two weeks polling by YouGov and Survation has shown the race to be tightening and even suggesting a hung parliament.

If correct, that leaves a considerable number of other pollsters quite far from getting it right, and history has shown us that exit polls have tended to be closer to the result.