He cites Tory dependency on pollsters, lack of real change on offer in Europe and blocking of parliamentary reform. He will resign his seat and trigger a by-election, the honourable thing to do. “I want change, I am an optimist”.

UPDATE: Guido asked Carswell to rate his chances: “I don’t know”. He confirmed he had not spoken to the PM this morning. “I wouldn’t worry Douglas, he’s watching live,” Nigel quipped. Carswell commented “I happen to like David Cameron, I’m not expecting him to reciprocate that now. He’s a nice person, he’s just not serious about change.”