With many Brexit polls shifting from a slight Leave lead to a slight Remain lead in the past few days, watching the referendum results roll out across Britian will prove to be compelling viewing. Looking at opinion polls, results from the 2014 EU election and the recent British general election, it's possible to set some helpful benchmarks for viewing since significant regional variation is expected.
This is how the evening should unfold.
10 p.m. (BST) / 5 p.m. (ET)
Voting closes in the nearly 400 local counting areas across Britain at 10 p.m. local time. No results from any area will be reported until it has counted all its votes, unlike in Canadian elections where numbers from each riding trickle in as individual poll boxes finish their counts. The size of each local counting area varies wildly, from smaller areas with just a few thousand voters, to larger cities like Leeds and Manchester, which will report hundreds of thousands of votes at once.
12:30 a.m. (BST) / 7:30 p.m. (ET)
Early results are expected after about two and a half hours of counting. Sunderland is expected to be among the first to declare its results, with the area taking pride in being the first constituency to report in each of the past six general elections.
Sunderland will be a very interesting test case for how the rest of the evening will unfold. A Labour Party stronghold located in the northeast of England, Sunderland won't necessarily follow Labour's advice to vote Remain. In the past EU election, the UK Independence Party placed a strong second, winning 30 per cent of the vote, and it performed well there in the past general election.
If Leave wins by a small margin in Sunderland – winning by between 2 and 6 percentage points –it will preview a close race nationwide. If Remain is able to come out on top, especially by a comfortable margin, it will be a good sign for its chances throughout the rest of the evening. On the other hand, if Leave is able to post a stronger-than-expected victory in Sunderland, then it can expect a good national result.
Other areas planning to report at around this time, such as Wandsworth and the City of London (the financial district inside of Greater London), are both anticipated to post strong victories for Remain.
1:15 a.m. (BST) / 8:15 p.m. (ET)
A significant number of votes from Northern Ireland should start to report at this point. Voters here make up nearly 3 per cent of Britain's population, but their views are largely ignored by pollsters, and it's difficult to get a handle on exactly how they're planning to vote. The few polls that have been taken expect a strong vote to remain in Europe, with nearly 60 per cent of voters expected to vote to stay.
At this point in the results process, Remain should be building up a lead, even if the overall vote is close nationwide.
2 a.m. (BST) / 9 p.m (ET)
By 2 a.m., significant numbers of Scottish areas are expected to start reporting. With most Scottish political parties campaigning to Remain, featuring enthusiastic support from popular First Minister Nicola Sturgeon, Scottish polling forecasts a strong sentiment for staying a part of the EU.
Welsh areas are also expected to start reporting at this time. All the votes reported up to this point, which feature many pro-EU areas, should definitely see Remain with an increasing lead if it has any hope of winning.
3 a.m. (BST) / 10 p.m. (ET)
At 3 a.m., results will start coming in quickly for several hours, with mixed news coming for both sides. In good news for Remain, significant parts of London will now start declaring their results. Remain is expected to perform better in Central London than in Outer London.
If Remain can rack up victories in Outer London regions, this will help its chances significantly. Given their electoral histories, Leave should perform well in places like Havering and Bexley. Areas like Sutton and Hillingdon should be closer to the overall national average, and either side performing well there will hint at who will win the overall vote.
The Leave campaign will also find positive news during this period, as the south of England, as well as parts of the East, will start reporting in greater volume. These are areas where UKIP has traditionally done best, and Leave will start quickly increasing their vote share as these areas announce their results.
More than half of all areas are expected to report between 3 a.m. and 4:30 a.m., and a clear picture of Britain's future in the EU will emerge during this busy reporting period.
6 a.m. (BST) / 1 a.m. (ET)
As if to inject a little extra drama to proceedings, areas expected to report the latest are also anticipated to be among some of the strongest results for the Leave campaign. Almost all of the areas planning to report at 6 a.m. local time or later are in places that were won by UKIP in the last European parliamentary election in 2014. Many of these late reporting areas are in the southeast, an area long represented in the European Parliament by UKIP leader Nigel Farage.
If the Remain campaign is only leading by a small margin at 6 a.m., these pro-Leave areas could easily flip the result in the other direction. If Leave is even marginally ahead at this point, it would be surprising for it to lose.
Paul Fairie is a political scientist in Calgary, where he studies voter behaviour. He helped design an award-winning, election-forecasting model with The Globe and Mail.