File 20170605 16915 14ctrjy.jpg?ixlib=rb 1.1

To sleep or not to sleep? Everything you need to know about #GE2017 election night

PA/Chris Radburn

To sleep or not to sleep? Everything you need to know about #GE2017 election night

It’s going to be a long night as the UK goes to the polls for its snap 2017 general election. So should you stay up all night or take a democracy nap? Here are the key moments to look out for and the seats which might indicate early on whether Theresa May has secured the thumping majority she originally envisaged.

The polls close at 10pm

The doors will shut and ballot boxes will be sealed up and transported to one of the counting centres across the UK. In some places, this involves travelling a significant distance, so delays can occur. In Scotland, helicopters have been used to transfer boxes from remote islands to the mainland.

Counting clerks will then work through the night to count the votes in most cases. If you’re feeling tired by this point, remember that many of these officials will have begun work at 6.30am (or earlier) setting up the poll.

Will there be an exit poll and will it be reliable?

IPSOS-Mori’s exit poll will be reported on the BBC and Sky News at 10pm as soon as polls close.

At the last election, the exit poll caused quite a stir. Announced on the BBC at 10pm, it forecast that the Conservatives would be the largest party. It took an immediate bashing with Paddy Ashdown infamously stating that he would “eat his hat” if it was correct. He had to eat his hat.

As it turned out, that poll was much closer to the eventual reality than polls that took place before the election. The exit poll is therefore a crucial clue as to how things will unfold.

We should nevertheless take exit polls with a pinch of salt. They’ve been wrong before, as they were in 1992. They are based on samples which may not be representative of the whole population, but exit polls do have the advantage of asking people what they really did, rather than what they intend to do at some point in the future.

When might we expect local results?

A local returning officer is responsible for the counts in their area and declarations will drip through during the early hours of the morning.

Sunderland traditionally works hard to make its announcement first. Constituents in Houghton & Sunderland South might hear their result as early as 11pm. The result in Sunderland Central generally comes an hour later. After that, things will go quiet. Then there will be a rush of results between 3am and 5am. A handful of constituencies will be as late as noon on Friday.

The distribution of estimated declaration times

When to expect results, based on information from the Press Association. Author provided

When will we know who has won?

Ah, that’s the million dollar question. “Winning” usually means getting 326 seats. This would allow the party leader to have a majority of the seats in parliament. They would then be able to form a government and pass policies without needing the support of another party.

There won’t be enough declarations for a party to have won 326 seats until 4am. And as many seats will go in different directions, it will be much later before a party has won enough constituencies to form a government.

No time to stop and chat in Sunderland. PA/Paul Kingston

But political scientists and the media will be identifying underlying trends from the early results to get a sense of the overall outcome. Armed with information about the underlying demographic and political makeup of constituencies, we can expect changes in voting patterns to be similar in similar constituencies (on average).

My University of East Anglia colleague Chris Hanretty estimated that Remain had only a 0.03 probability of winning the Brexit referendum by 2:03am. It was zero by 3am. That was long before the politicians (and media channels) cottoned on to what was unfolding. Watch for such forecasts again.

When will we know who the next PM is?

If there is decisive victory with one party winning an overall majority, then that party leader will be quickly confirmed as prime minister on Friday morning.
But if no party reaches the magic 326 seats, then there might be some wait. Negotiations will begin between parties about whether they could form a coalition to take them over that threshold. In 2010, it took five days for the Cameron-Clegg coalition to form. There was some surprise in Britain that this process took so long. But in some countries it takes much longer – 541 days after the Belgian elections which took place at around the same time.

And what if Theresa May wins a majority – but a much less handsome one than David Cameron in 2015? Given that a landslide was originally predicted for this election, she might even face an internal coup.

Could any seats give an early indication?

If the Conservative party shows signs of winning seats off other parties then they are on track to stay in government. Chris Hanretty has helpfully identified a list of those predicted gains for the Conservatives.

The table below lists the first 25 of these to be called. If they turn blue as expected, Theresa May will be on course to stay in power with an enhanced majority (and 365 seats, according the electionforecast.co.uk predictions).

So should I stay up … or go to bed?

The hard-core psephologist stays up, and stays the course. The more sensible, normal person stays up for the 10pm exit poll, necks a hot chocolate and gets some kip. Be up early for 4am and you should still have plenty to see. But then again, British politics has been rather unpredictable lately.