Social media users have barely been able to contain their delight at claims in a new biography that British Prime Minister David Cameron put "a private part of his anatomy" into the mouth of a dead pig at an initiation ceremony while he was a student at Oxford University.

The allegation was published in Call Me Dave: The Unauthorised Biography and attributed to "a distinguished Oxford contemporary" who is himself an MP, co-authors Lord Michael Ashcroft and Isabel Oakeshott said.

Controversy: David Cameron. Credit:Getty Images

The act was allegedly performed at an event hosted by the notorious Oxford dining club, the Piers Gaveston, named in honour of the supposed lover of King Edward II of England.