Brexit poll: In or out? British bookmakers see more bets placed on Britain staying in European Union

London: British bookmakers on Thursday afternoon revealed that the final flurry of bets placed on the outcome of the "In/Out" referendum on European Union (EU) membership were strongly backing an "In" result.

Odds released on Thursday afternoon by Ladbrokes, one of Britain's largest betting firms, showed the "Remain" camp at 1/10 and "Leave" at 6/1, which would mean an 86-per cent likelihood of Britain remaining in the EU.

Odds from another betting company, Betfair, were similar with Remain at 2/13 and Leave at 6/1, again an 86 per cent likelihood of Remain winning, Xinhua reported.

Ladbrokes also revealed that heavy betting on Remain had taken place in the last 24 hours, with one million pounds ($1.48 million) bet.

Most of those bets are on Remain, with the average Remain bet at 400 pounds and the average Leave bet at 70 pounds.

Twitter users were posting many more tweets supporting an In result than an Out result.

Tweetgraph, a Twitter-tracking platform developed by digital agency Blueclaw, showed tweets backing Remain outnumbered tweets backing Leave by two to one.

"We're surprised by the strength and speed of the shift," said Blueclaw managing director Aidan Cook.

"The two camps have been in close competition in the build up to the vote. Suddenly, we're seeing a significant gap opening up; the online debate seems to have switched to terms concerned with ' Remain'," Cook added.

Polling stations for the referendum stay open until 10 p.m. local time with a result expected by 7:00 a.m. on Friday.