Brisk voting was reported and members of the public posted photographs of busy polling stations across the country.
Both sides of the campaign have appealed to a record number of registered voters -- more than 46 million -- including 1.2 million British Indians, for a big turnout as Prime Minister David Cameron made his final appeal to "get out there and vote Remain" and reject the "untruths" of the camp in favour of 'Brexit' or Britain's exit from the European Union (EU).
"It is a fact that our economy will be weaker if we leave and stronger if we stay," Cameron told supporters in Birmingham yesterday as he travelled up and down the country to make a final push for votes.
As part of his closing speech, he invoked Britain's popular war-time Prime Minister Winston Churchill, saying, "The greatest privilege of my life is to stand in my office two yards away from where Winston Churchill made that decision to fight on against Hitler in 1940. He didn't want to be alone, he wanted to be with the Poles and the French and the others fighting for European freedom and democracy."
More From This Section
A late boost for the Remain camp came from an Ipsos Mori poll, giving it a 52 per cent against 48 per cent for Brexit. The phone-based survey was completed in the last few days before the referendum and marks the most definitive lead yet for those campaigning for the UK to remain a member of the 28-nation economic bloc.
Poll tracker of 'The Daily Telegraph' and and a YouGov poll for'The Times' both showed Remain at 51 per cent and Leave at 49 per cent, reflecting the neck-and-neck nature of the campaign throughout the four-month period since Cameron announced the date of the referendum in February.
Last night another poll, by ComRes, gave Remain an eight-point lead with 54 per cent compared to 46 per cent for Leave.
The referendum ballot paper asks the question, "Should the United Kingdom remain a member of the European Union or leave the European Union?"
Voters have the option to mark a cross next to either "Remain a member of the European Union" or "Leave the European Union" and whichever side gets more than half of all votes cast will win.