Boris Johnson (L) and Michael Gove on the Vote Leave campaign trail. Carl Court / Getty The betting odds for the EU referendum changed direction over the weekend and now firmly favour a Remain vote with just three days to go.

Last week many bookmakers had predicted a Leave Vote to be the odds-on favourite by the weekend, with over 72% of bets on a Brexit, but that has not happened.

Ladbrokes has given just a 27% chance of a Vote Leave while William Hill has it as 28.5%. Ladbrokes added that 95% of betting on was a Remain vote on Monday.

Matthew Shaddick, head of political betting at Ladbrokes, said the shift back towards Remain had been "significant."

"Looking closely at the figures," he said, "the proportion of money being placed on Leave hit its peak a couple of weeks ago. The picture certainly looks significantly different to last Monday.”

Will Hill spokesman Graham Sharpe, who last week called the Brexit markets extremely "volatile," agreed that Remain was now the most likely outcome in the betting.

''Remain has indeed remained favourite ever since the date of the Referendum was confirmed in February," he said,"although it has been both shorter and longer odds during the course of the campaign."

He added that most bets were still on a Leave, and that such an outcome in the June 23 referendum would hurt William Hill's bottom line: "Leave has attracted by far the greater number of bets in total and is the result we fear financially. Despite having taken bets of £100,000 ($146,170); £60,000 and £40,000 for 'Remain' we still stand to pay out much more should Leave win."

Here are the Vote Leave odds as of Monday morning:

Ladbrokes — 11/4

William Hill — 13/5

Paddy Power — 11/4

Sky Bet — 11/4

Coral — 12/5

Betfred — 11/4

Betfair — 11/4

As Business Insider previously noted, odds and polls carried out more than few days before a referendum often fail to take into account the usual shift towards the status quo in the final week.

In a Brexit note released last week, HSBC warned that "poll volatility ahead of a vote is not uncommon" and that pollsters and betters for the Scottish referendum were taken by surprise when the country voted "No" to independence.

Whichever way the vote goes, the number of bets on the EU referendum has been huge. It has become the biggest market for any UK political event ever, with the number of bets reaching football World Cup proportions. More than £30 million ($42 million) has been bet, compared to £35 million bet on the 2014 World Cup.

Brexit polls appear to have followed the betting odds, with a Survation poll for the Mail on Sunday giving Remain a three-point lead.