DIFFERENCES between David Cameron and Lord Ashcroft, one of the Tory Party’s biggest donors, have been simmering for years, but the peer’s book, which will be published next month, has brought them into the open in cataclysmic style.

The contents of Call Me Dave contain a number of allegations about Cameron during his time as a student at Oxford, including his alleged membership of a drinking group called the Bullingdon Club and the Piers Gaveston Society – a men-only dining club that was said to encourage “ostentatious decadence”.

It was during his initiation into the latter group that the incident involving the pig was alleged to have happened.

Formed in 1977, the society also counted among its members actor Hugh Grant, Private Eye editor Ian Hyslop and London Mayor Boris Johnson.

Sources close to the Prime Minister said they “did not recognise” the accusations, which include claims Cameron was present at events where drugs were taken and took part in a bizarre initiation ceremony which involved inserting “a private part of his anatomy” in the mouth of a dead pig.

Twitter went into meltdown with the story yesterday and #piggate and #DavidHameron were two of the hashtags that were trending all over the world.

Social media was awash with claims the story was “porkies” and cleverly edited photographs of Miss Piggy and other porcines.

Pete Wishart, chairman of Westminster’s Scottish Affairs Committee, tweeted: “This Tory Government will be remembered in two distinct parts. The bit before #piggate and the bit that follows.”

And Angry Salmond wrote: “I’ve been describing the Tory mentality as ‘hogwash’ for years.”

The claims are likely to overshadow the Tory conference which takes place next month, and Ashcroft was refusing to back down. He admitted that he had a “personal beef” against Cameron after the PM failed to offer him a significant job in his administration after the formation of the coalition government in 2010.

The Pig Issue: Cameron’s reputation in ruins after intimate porcine claims

Cat Boyd: Cameron's unnatural union with a dead pig's mouth tells us much about him

Michael Gray: Piggate is irrelevant, it is real issues that matter

The National View: A penchant for pig? Fine, but it's the other revelations that really damn Cameron