Britain's bookmakers have witnessed a surge in betting as voters across the UK go to the polls and punters attempt to predict the result of the EU referendum. Matthew Shaddick, head of political betting for Ladbrokes, told IBTimes UK that his firm had shortened the odds for Remain a victory from 1/4 (76%) to 1/7 (87%), while the odds for a Leave result had lengthened from 4/1 (20%) to 9/2 (18%).

"Most of the actual bets are for Leave, most of the money is for Remain – around 85% of all the money we've taken this morning and overnight is for Remain. There was a big a move first thing this morning, anticipating good polling news for Remain," Shaddick explained.

"This will be the biggest day of the campaign [for taking bets], but that's always the case for elections – most of the money you take is on the day before or on the day itself. It does look like it's going to bear our previous record for most money taken on a political betting market."

Betfair had also recorded a surge in betting on 23 June. Naomi Totten, a spokesperson for the bookmaker, told IBTimes UK: "This market has pretty much blown out all of our expectations in that it's already trading at £55m, £5m of that was taken this morning. So we are anticipating quite a lot more for today."

The bookmaker has the momentum behind Remain this morning, with the price coming in from 1.3 (1/3 or a 77% chance) to 1.17 (2/13 or an 86% chance). Meanwhile, William Hill also made Remain their 2/9 favourite (81% chance), with Leave offered at 3/1 (25%).

"We have been taking bets on the outcome of an EU Referendum since January 20, 2013, when a customer from Jersey staked £20 on Leave – at that time the odds were 8/11 (57%) 'Remain, Evens, (50%) Leave, the closest they have ever been," Graham Sharpe, a spokesman for the bookmaker. "Now there is some £20m riding on the outcome with fixed odds bookmakers."

The final EU referendum telephone opinion poll from Ipsos MORI for The Evening Standard, of more than 1,500 people between 21 and 22 June, put Remain on 52% and Leave on 48%. Polling stations are open across the UK between 7am and 10pm BST. There will be no exit poll straight after the vote, like at general elections, but YouGov is planning to publish an on-the-day survey at 10pm on Sky News.