Book details Cameron’s hazy days in college

The book, co-written by the journalist Isabel Oakeshott and Conservative donor Lord Ashcroft, claims that there is even photographic evidence of the Prime Minister putting “a private part of his body into a dead pig’s head”.

The book also claims that Mr Cameron smoked marijuana at university.

Times of India reports that the biography, “Call Me Dave“, says that the young David was a member of the Piers Gaveston Society as an Oxford University student.

Ashcroft’s status, which meant he did not have to pay British taxes on overseas earnings, caused a major scandal at the time and Cameron’s office said the prime minister had only found out in 2010.

The person who is said to have the pictures did not respond to the authors’ request for comment.

The alleged act echoes the first episode of the drama series Black Mirror, in which the fictional Prime Minister has sex with a pig live on TV.

It has always been rumoured that Mr Ashcroft and Mr Cameron had suffered a falling out. In less scandalous revelations, Cameron’s friends from his Oxford days say he liked to sit in his dorm room smoking pot and listening to Supertramp.

The Prime Minister’s official spokeswoman said: “I am not intending to dignify this book by offering any comment”.

David Cameron had a hard start to the week, as he awoke on Monday morning to the Daily Mail’s headline, “Revenge!”

It is also claimed that Lynton Crosby, the Australian strategist who masterminded Mr Cameron’s 2015 election victory, described the Prime Minister as a “tosser”.

He told the Spectator: “As far as I know David Cameron was never a member of the Piers Gaveston Society, so there would have been no need for an initiation ceremony”.

Mr Cameron has already confessed to being “desperately embarrassed” about his membership of the hard-drinking Bullingdon Club, and the latest stories of excess are similarly uncomfortable. “The critical thing in all of this is that those of us who are in politics mustn’t be hypocrites”.