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People all over the world will be watching closely on Thursday night and Friday morning to divine the result of Britain’s referendum on EU membership. It could prove a long vigil.
You can follow events here in the UK and reaction from around the world on our live EU referendum blog.
Will exit polls give an early steer?
No. On the night of the general election last summer, the scale of David Cameron’s achievement was clear — albeit thoroughly surprising — just after 10pm when the BBC exit poll came in: the Conservatives had beaten Labour and the Lib Dems and managed an outright majority.
There will be no such early moment of clarity on the referendum result because there will not be a formal exit poll. But there will be at least two polls on the day, from Ipsos Mori — taken earlier in the week — and YouGov, who will poll on the day and release the numbers at 10pm. City types may also study the movement of sterling, given that some institutional investors have commissioned their own private polls.
How much use are previous elections?
Not much. There are no easy comparison points for analysts seeking to make sense of the numbers.
There will be 41,000 polling stations at 382 local counting areas. These are not the same size and shape as Britain’s 650 constituencies. Experts have pinpointed some of the seats that appear to be clearly In or Out but this is based on general election geography.
Will the level of turnout have an impact?
Low levels of turnout ought to favour the Leavers, who are thought to be more motivated by their antipathy towards the EU. Somewhat higher turnout should maximise the Remain vote, given that younger people — who tend not to show up to vote — are more likely to be Europhile.
But if turnout reaches exceptional levels — say, 80 per cent or more — this could suggest an advantage for Leave as it implies that the most anti-establishment, anti-EU citizens, who might never normally bother to go to the ballot box, have come out in favour of Brexit.
How will the regions vote?
Experts are confident of certain patterns: that London, Scotland and Northern Ireland will be heavily In and that the Midlands and the north west will be Out. Post-industrial heartlands are likely to vote to Leave while university towns are more likely to be Remainers. Bookmakers offer just 2:1 on Edinburgh having the highest proportion of In vote, followed by Cambridge, Oxford, Islington, Hackney, Southwark and Brighton.
The first results arrive — from Gibraltar and the Scilly Isles — though neither will tell us much about the national picture.
The first big conurbation to declare should be Sunderland, where there has been strong support for the United Kingdom Independence party in some former Labour areas.
Here, the Leave campaign will need a solid lead — maybe six points or more — to suggest it is on track for victory. Newcastle upon Tyne, which should come around the same time, ought to deliver a Remain vote; if not, it bodes ill for the prime minister.
Next up is probably the City of London, where anything other than a thumping In vote from its 7,000 residents would be astonishing.
We should see another result come in from Swindon, once declared Britain’s most “average” town: that does not mean it will reflect the entire country, however. Data suggest Swindon will come in strongly for Leave. Darlington, another railway town, has also been leaning Leave, albeit only slightly. Watch this one closely for a clear result either way.
A clutch of Belfast results should come in around now — Northern Ireland is expected to back Remain. On the other side of the ledger will be a raft of Eurosceptic results from Hartlepool, Basildon, Stockport, Salford and Merthyr Tydfil.
Remain should be boosted by a host of Scottish results, including East Ayrshire, Angus, North Ayrshire and Clackmannanshire.
Enfield, in London, should arrive around now. If it votes for Leave then the prime minister could be heading for the political scrapheap.
At this point the In and Out camps will have a very good idea of how the vote is heading thanks to their activists at thousands of polling booths around the country, who will be watching the boxes stack up. “In an election it’s quite a tricky exercise but this time there are only two options so it should be quite easy to judge,” said one party official. “The parties will have a much better idea than you might think.”
When will we know the result?
The overall picture could be clear, reckons polling expert Chris Hanretty, when Lancaster reports; by then about 200 results should be known.
There is another flood of results due including London boroughs such as Tower Hamlets. Hackney lands at 4.30am, Kensington at 5am.
Among the last counts to arrive around this time will be from Bristol, followed by Harborough at 7am. It is not impossible there could be recounts but these would be local rather than national: the only challenge to the overall result can be via a judicial review. If the result has not been “called” by broadcasters and news agencies by this point, it could be because the numbers are very close.
Once all the regional totals have been declared, Jenny Watson, the chief counting officer, will declare — in Manchester Town Hall, probably around breakfast on Friday June 24 — the result of the UK’s referendum on membership of the EU.