I think the PM lost his right to sue for libel on anything football related after he libelled himself by falsely claiming to support West Ham.
Technically falsely accusing someone of a criminal offence is actionable per se, so Cameron could get round the fact that it's impossible for a right minded person to think less of him when he's already said he's a W*** H** fan.
I haven't deleted Barna's post though because I think it would be hard for anyone to suggest that it should be taken seriously in the context of his contributions to this thread.