The largest wager to date for the Leave camp has been placed with bookmakers Ladbrokes.
An online male customer has placed £20,000 on the likelihood of the UK voting to leave the European Union, which sees the firm's betting barometer showing there's a 33% chance of Brexit occurring.
It remains an odds-on shot at 2/5 David Cameron has his way and the country remains within the EU.
Jessica Bridge of Ladbrokes told BetOnPolitics.co.uk: "BoJo's mojo is starting to attract some serious cash from punters. It's the largest wager we've seen on the Brexit so far and looks like it could be a big vote of confidence for the leave campaign."
Ladbrokes latest betting
EU referendum
Remain 2/5 (67%)
Leave 15/8 (33%)