Rarely can a ministerial resignation be less mourned than Liam Fox’s. An intriguing aspect of his fall is explained in my book The Clegg Coup. Senior Lib Dems and Tories told me repeatedly how Cameron and Fox loathed each other. Indeed, Cameron would often ring our Nick Harvey rather than his Fox to the extent that Harvey became known as “Cameron’s man at the MoD”.

“Fox sees himself as the prince across the water,” I was told. “He thinks Cameron never faced a proper challenge for the leadership because he [Fox] was edged out in the first round by David Davis, whom he considers flaky. Liam is not going to blow his shot too early and it’s a good way off, but I do think he wants to challenge Cameron for the leadership.”

Fox, I was also told, privately opposed military operations in Libya, calling it a “Number 10 caper” and didn’t believe it would work without significant ground forces. “David Cameron’s attitude to the MoD was ‘go along and do it, chaps.’ It was a real eye opener. Everyone at the MoD, including Liam Fox and the generals, were opposed.”

For all the media focus on Lib Dem difficulties, a picture emerging from The Clegg Coup is that the Tories are essentially two parties within one and their attitude to Cameron – and Clegg – varies massively from minister to minister. Figures such as Michael Gove and David Willetts will line up with Nick and Vince Cable against Theresa May on immigration – and I detail several similar examples.

All of which might explain why Cameron perhaps didn’t fight as tenaciously as he might to defend his “friend and colleague”, alias “Thirteen Century Fox”…

You can buy The Clegg Coup by Jasper Gerard from Amazon here.