Prof John Curtice, whose team of polling experts is analysing the results of today's election, tell the BBC's Newsnight: "We may end up discovering by the end of the night that not as much has changed hands as much of the early commentary anticipated."

Assessing the relative expectations of the major parties, Sir John says a lead in the projected national share of eight or nine points would be a good result for Labour. If the Conservatives were "even-stevens" with their rivals, they would probably be happy, he suggests.

As ever, local issues can swing results against the national trends, with a "crucial battle" in Labour-held Sheffield, Sir John says.

"There's an enormous row about the cutting down of trees, with which the Labour Party is associated," he says, adding that Labour might lose ground as a result.

Newsnight political editor Nick Watt, in Wandsworth - one of the Conservatives' "Crown Jewels" - reports that Labour is saying privately it might just gain the council but would have to overturn a large majority.

"The word is that it's going to go down to the wire at about 2am or 3am," he adds.

Labour sources tell the Press Association the party has a "fighting chance" in elections in the London borough of Barnet but that Westminster, Wandsworth and Kensington and Chelsea are "out of reach".

There has been anger in some areas piloting controversial ID trials after people reported being prevented from voting, the Press Association reports.

Bromley, Gosport, Swindon, Watford and Woking councils have all trialled the scheme to help cut down voter fraud. But MPs and councillors said people, including elderly residents, were being turned away because they did not have appropriate ID.

Angela Wilkins, leader of the Labour group in Bromley, said five people had been unable to vote as a result of the pilot and that the scheme was also causing long delays.

The presiding officer at the polling station in Sydenham Tennis Club, in Bromley, said "only a very small percentage" of voters had forgotten or were unable to provide ID.

Local MP Ellie Reeves said she knew of two people being turned away from polling stations in Bromley this morning.

In Woking, Labour councillor Tahir Aziz said a man had been turned away from a polling station in Walton Road because his photo ID - a Surrey County Council document - was not accepted.

"This gentleman turned up, showed his ID which included a picture that was clearly him, it was an exact resemblance, but they wouldn't accept it as it was not on the list of acceptable forms of ID," said Mr Aziz. "He was fuming. He was furious. He is a British national and he couldn't vote."

Sir John says his team will calculate the BBC's Projected National Share, an estimate of the share each party would have polled across Britain, had the pattern of voting in local elections been replicated in a parliamentary election.

He says: "The PNS will provide the simplest measure of how well each party has performed, and how their vote this year compares with past local election performances, not only recently but also in the more distant past."

However, he adds that the PNS will not be published until his team are confident their estimate is correct, which might well be on Friday afternoon.

Image source, PA

The Labour Party is almost certain to make big advances in London, potentially taking some of the Tories' totemic councils like Wandsworth and it's not impossible they'll take Kensington too.

But London is already a Labour city. The harder test for them to pass is to show that they can advance, in parts of the country where there are marginal Westminster constituencies - Swindon, Southampton, Watford.

For the Tories, it is a case of stopping the rot. They dropped back, relative to Labour, in the general election.

Traditionally, the governing party loses significant numbers of seats in local elections. But Theresa May is vulnerable. Her supporters have been fighting to stop the slide.

It's possible, though, that the results may not see swathes of the country change hands.

Read Laura's analysis in full

Image source, Jeremy Corbyn and John McDonnell

The local council elections in England are being held in predominantly Labour-held areas. The party holds more than half the seats that are being contested.

So with the two main parties neck and neck in national polls, you would expect Labour to win more seats given that they are playing on home turf.

But there is still room for improvement.

Read Iain's analysis in full.

Polling expert Prof Sir John Curtice and his team are preparing to pore over the results. And he's been offering some insight into how they go about it. The psephologist says headline figures of losses and gains can prove misleading in years like this, when as many as 42% of seats being contested are in London.

"So, we will also be looking at actual votes cast – in 50 of the 150 councils where elections have taken place today," he says. "This will enable us to... report and analyse by how much the parties’ support has risen and fallen, and on where each party has performed best or worst.

Image source, bbc

"We will address questions such as, has London voted differently? Have voters in Remain voting areas behaved differently from those in places where Leave prevailed? Have areas with lots of younger voters swung differently from those with an older age profile?"

The analysis will be based on changes in support since the local elections in 2014, when most of the seats up for grabs this year were last contested.