I have always believed that there should be debates between the three main party leaders in general election campaigns. Sky News have now upped the ante and issued formal invitations to the three party leaders to take part in an election debate. David Cameron has already accepted and it is safe to say that Nick Clegg will follow suit. It's a clever move on Sky's part. If Gordon Brown is sensible he will accept too, but if not, and Sky empty chair him, could the Labour Party then call on Ofcom to intervene and order Sky not to go ahead?