Polling booths across the UK to vote on the country's EU membership have now closed.
Both the Remain and Leave camps look to have a long night ahead of them as counting now gets underway.
The Electoral Commission has said if you're in line at a polling station at the 10pm cut-off you'll be able to cast your vote.
The first areas to announce their results are likely to be Sunderland, Newcastle-upon-Tyne, Gibraltar and the Isles of Scilly from around 11:30pm.
The City of London booths will be all counted and a result announced by 12:45am, the same time as Swindon.
Read more: EU referendum map: Live results updates
Both sides of the referendum debate sent out last minute pleas for votes in the final two hours.
Boris Johnson urged recipients: "Don’t lose this chance to make today our Independence Day!"
Meanwhile Labour's Remain camp echoed the urgency, writing: "If you haven’t voted yet — don’t miss out on being a part of it."
In London, torrential downpours and localised flooding could play a part in voter lower turnout – trains on commuter lines to the south of the city were severely delayed, with Waterloo station particularly affected, leading many commuters to complain they may not get home in time to vote at their local booth.
Leave campaigner Nigel Farage earlier in the day suggested the bad weather would be a turn-off for those voters he classed as "soft-Remain".
Anecdotal reports from around the UK, however, suggested a healthy turn-out – although in Scotland it is thought to not be as high as its independence referendum in 2014.
However, official local turn-out results won't be known until just before each returning officer announce their results.