LONDON The odds of Britain voting to leave the European Union in a June referendum narrowed on Tuesday as attacks in Brussels that killed at least 34 people were seen boosting the 'Out' campaign.
Bookmaker Paddy Power narrowed its odds on a Brexit to 7/4, or 36 percent, from 2/1, or 33 percent, on Monday. Betting website Betfair also shortened its odds to 36 percent, while four major bookmakers, including Bet 365 and Sky Bet, narrowed their odds to 6/4, or 40 percent, following the attacks.
PredictIt, a political prediction website run by Victoria University in Wellington, New Zealand, said the chances of an 'Out' had increased to 45 percent.
"What we've seen today in Brussels ... may sway people (towards voting to leave the EU), so I think that's why the bookies have shortened the odds," said Chris Hawkes, a currency trader at ETX Capital in London.
"The average man on the street doesn't really understand the ins and outs of a Brexit, and border control seems to be one of the primary concerns, so when we see attacks that we've seen today this is going to make people more staunch on their standpoint," he added.
Some advocates of a "Brexit" claimed the EU's open border policy had allowed the attacks on Brussels' main airport and a rush-hour metro train to take place.
Bookmakers' odds on a vote to leave the EU had already been tightened after a leading eurosceptic Cabinet minister resigned on Friday over measures contained in last week's budget, highlighting divisions within the ruling Conservative party.
(Reporting by Jemima Kelly; Editing by Catherine Evans)