Species purity alarm: David Cameron and the pig's head

Not much separates the human from the non-human animal. And humans have never been comfortable with this obvious familiarity, hence the strongly enforced distinction between species. The great taboo of bestiality blurs this separation and factures the boundaries. No surprise then that the recent allegations of UK Prime Minister David Cameron's student initiation ceremony involving a sex act with a dead pig has set the British media ablaze.

The allegations are disclosed in Lord Michael Ashcroft's new unauthorised biography Call Me Dave. The Daily Mail – which is serializing the book - called the initiation event into the Piers Gaveston Oxford dining society "obscene", 'sordid" "outrageous" and "debauched".

The Guardian was hard pressed to get excited enough to even find an adjective to describe further revelations that Cameron joined friend James Delingpole at his room at Christ Church College, Oxford and "smoked cannabis occasionally while listening to Supertramp as part of a group called the Flam club."

No, the inference seems to be, a little dope dabbling is a fairly accepted, if not mandatory part of undergraduate life, even for someone who is now Prime Minister. Not so acts with a dead pig involving 'privates'.

While there are allegations that Ashcroft dished the dirt because he was passed over for a significant government job, the fallout has gone beyond simple embarrassment and humiliation for the PM and entered into the realm of animal rights abuse.

According to NME, Morrisey, a highly regarded UK musician, has issued a joint statement that he claims is also sent on behalf of animal rights group PETA.

The statement reads, "No, boys won't be boys - not when it's sexual perversion and also involves a vulnerable victim of slaughter, a feeling being who lost his or her life and then was used for a prank…A prime minister is supposed to protect the most vulnerable."

Indeed, one of the problems with bestiality is the issue of consent. Can an animal ever consent to an act of intercourse with a human? There is the issue of power imbalance, for a start.

Any encounter where one party can be legally skinned, made into a handbag and also eaten is not on an equal footing in the bedroom. But if one partner is dead, then the issue of consent surely need not apply.

Other taboos, such as necrophilia step in. But the fact that the pig was dead when Cameron allegedly stuck 'a private part of his anatomy' in the pig's mouth doesn't seem to be the issue. The uproar about this allegation surrounds the taboo of bestiality, not necrophilia. By demanding that human beings do not engage with animals in sexual acts, the act of prohibition defines the differences between the species.

Humans have long had a great fascination for sexual activity between creatures of different species. In his 2001 paper Heavy Petting philosopher Peter Singer argues that instances of sex across the species barrier are so frequent "it ceases to be an offence to our status and dignity as human beings." No mention of the animal's dignity.

We live in an era when many former sexual taboos, such as inter-racial sex and same sex relationships are far more visible and socially acceptable in the Western world. Sado-masochism and bondage have left the hushed back rooms of sex shops and hit the bestseller lists, through works such as E.L James' Fifty Shades Of Gray.