Interesting article by Isabel Hardman in today's Observer: http://www.theguardian.com/commentisfree/2016/feb/07/europhobe-tories-ruin-david-cameron-dream
"Cabinet ministers who want to campaign for Britain to leave the EU are not at all happy. They had been pleased that they would get a free vote on the matter and had planned to keep up their side of the bargain by repeatedly calling for civility between the two camps in the Tory party. Now they mutter darkly that the campaign will be much more personal and aggressive. Those involved in the voluntary party are threatening to abstain from campaigning in the mayoral and local elections as revenge for Cameron’s advice that Tory MPs should “not take a view because of what their constituency association might say”.