Election results timeline: exit polls, first results, swing seats to watch

Britain began voting early on Thursday to decide the shape of its new government but with confidence in opinion polls shot to pieces in recent years there will be no firm idea of the result until two hours before midnight - and if it's tight this will mean every single local result counts.

Polling stations opened at 0700 BST this morning and will close at 2200, with election restrictions preventing the publishing of opinion polls on the day until after polling closes.

Just after the booths are closed, Ipsos MORI will publish the official exit poll commissioned by the BBC, ITV, and Sky, which will give a projection of the ultimate number of seats won by each party.

Unlike in 2015, Paddy Ashdown is unlikely to declare that he will "eat his hat” if it is correct this time, as these forecasts continue to prove very accurate, with predictions never more than 15 seats out for the winning party. But if the exit poll projections are tight – ie within a 20 seat majority for the Tories - we will need to wait until the following morning to know whether there will be a Conservative majority, Conservative minority or Labour coalition.

The vote count begins straight after polling stations close, with the first results typically declared in Sunderland between 2300 and midnight and around 70 results by 0200 on Friday.

Then the deluge begins, with around half of the declarations arriving by around 0400, giving a firmer idea of the result, with close to nine out of 10 declaring officers having spoken by 0600.

In the case of a clear majority for the winner, the leader of the losing party will concede to allow the victor to claim victory, but in 2010's hung parliament it took another six days for a coalition to be decided. In 2015, David Cameron accepted victory just before 0600.

SEATS TO WATCH

In case of a close result, bellwether seats to watch are Carlise, Clacton, Southport, and Westminster North.

The top 'marginals' - those with the smallest majorities from the 2015 vote - are led by four Tory seats and three Labour: Bury North, Peterborough, Thurrock, Vale of Clwyd, Ynys Môn, Ealing Central and Acton, Hampstead and Kilburn, followed by Tory Telford, and LibDem East Dunbartonshire.

"In the UK’s first-past-the-post constituency level system, marginal seats are crucial in defining the outcome of elections," noted Deutsche Bank, which compiled a list of potential swing seats to watch based on different criteria, ranked by the expected timing of their declarations on election night.

However, strategists suggested that with the Brexit referendum last year and leadership changes across the major national parties since the last election in 2015, "it may be that a traditional margin-based seat list is less appropriate than in the past".

For Labour, areas of big Brexit votes are led by Wrexham, Clwyd South, Hartlepool, Delyn, Alyn & Deeside and Bishop Auckland.

For May's mob, large "remoaner" areas include seats in Bristol North West, Brecon & Radnorshire, Watford, Canterbury, Gower, Croydon Central and Twickenham - where LibDem grandee Vince Cable is confident of winning his old seat back.

Scotland presents a third interesting case, where there are several SNP seats with Conservatives in second place and apparently polling reasonably well.

These SNP seats are Perth and North Perthshire, Moray, Dumfries and Galloway, West Aberdeenshire & Kincardine, Banff & Buchan, and Berwickshire, Roxburgh & Selkirk.

Some of these seats were identified by Chris Hanretty of the University of East Anglia as a means of easily identifying whether the Conservative party are winning seats off other parties in order to add to their majority. These are 25 predicted gains for the Conservatives.