David Cameron has reportedly issued a plea for unity among his party's MPs tonight, warning them to be careful what they post on Twitter.
The Prime Minister called a meeting of his backbenchers in Westminster after a damaging bout of leadership speculation.
Pressure has been mounting on Mr Cameron to adopt striking right-wing policies in the wake of the party's disastrous Eastleigh by-election showing.
Home Secretary Theresa May fuelled rumours that she is positioning for a post-Cameron era over the weekend by delivering a speech that ranged far beyond her brief.
Defence Secretary Philip Hammond has also taken negotiations over the 2015-16 spending review public by calling for deeper cuts to welfare.
They were also told to stress that the next election would be a choice between having Mr Cameron or Ed Miliband in Downing Street.
Most of the interventions at the private meeting were said to be positive and supportive of the leadership.
However, Totnes MP Sarah Wollaston apparently pointed out that Mr Crosby's call for discipline had been leaked to the media beforehand - asking whether the rules applied equally to the top of the party.
I cannot 'participate' without the freedom to 'comment', even if that is sometimes inconvenient to the Executive
At the session this evening, Mr Crosby - an Australian who masterminded London Mayor Boris Johnson's re-election - was said to have reminded MPs that they were "participants not commentators".
The politicians were urged to focus on issues where the Conservatives polled strongly against Labour, such as welfare reform and the promise of an in-out referendum on EU membership.
The irony is that many of the appealing policies promoted by UKIP are already Conservative ones, but ppl don't realise this because....
......of mixed messaging.
Others complained that Cabinet ministers did not seem to be bound by the same restrictions, while Keighly MP Kris Hopkins reportedly criticised "self indulgent buffoons" touting themselves as alternative leaders.
So called "lurch to the Right" (sic) is popular. Are you lIstening PM?http://t.co/mYoIhFMy2C