Ladbrokes seems to be pretty impressed at the text of Donald Tusk's letter to European heads of state, suggesting a renegotiated relationship for the UK.
Today it said that since David Cameron started his negotiation process, the odds of Britain voting to stay in the EU have fallen from 4/7 to 1/3, while the chance of Brexit have risen to 9/4, from an all-time low of 5/4.
Essentially, that means the chances of the UK staying in the EU are now 71 per cent.
Meanwhile, the bookmaker reckons June is the odd-on favourite for the referendum, which odds of 4/6 it'll happen then.
Tusk published his letter this morning, outlining four "baskets", including new deals on economic governance, competitiveness, sovereignty and social benefits and free movement.
Reactions have ranged from optimism from the likes of Britain Stronger in Europe chair Sir Stuart Rose, who said the deal would give the UK "the best of both worlds", to rather less optimism from Ukip leader Nigel Farage, who dismissed it as "pathetic".