We now know that the  debates will take place in three English cities, upsetting the Welsh and Scots, and that they will be termed “Prime Ministerial”, pleasing Nick Clegg. We also know that some 76 protocols are in place to ensure no-one gets an unfair advantage.

As Dominic Lawson put it, “the effect is to ensure that the entire affair will be characterised by a depressing combination of rigidity and superficiality”. The approach is lifted from America where even Obama in his clash with McCain was “rendered soporifically dull by the rigid entirely unspontaneous format.”

What will this mean for our three contestants? Well rehearsed and prepared, as they each will be, to deliver their prepared statements, debate  for a minute or so, and reply to planted questions, the chances of any competitive advantage from what they say, the policy content, are zero.

So, we will be left with judgement based almost entirely on looks. “Do we like this person?”

 All the non-verbal clues will be in play. Tone of voice, gestures, facial expression, genuine warmth, natural smile, ease of body language, eye contact, all the normal signals of a confident personality but all under threat from the  television camera.

David Cameron has the toughest job. Once  the ‘charismatic telegenic’ performer his aura is diminished along with the Incredible Shrinking Man (Gerald Scarfe cartoon) polling figures.  As the still just-favourite he has most to lose and the temptation will be to try too hard. He needs the confidence to relax and take cues from Bill Clinton at his charming best.

As the least exposed and with no real form, Nick Clegg should go in with confidence high, certain that his freshness will give him an edge. We have little idea of what he stands for so anything he says will seem original. He can, and should come across as the one enjoying himself, so we might enjoy him.

Gordon Brown as ever is unpredictable. Recently his public preparation is the best. The Piers Morgan show and then 4 hours of Iraq enquiry will have fuelled confidence in his newly found ‘nice Gordon’ persona. If he can combine the nice with the formidable authority, lacking in both his fresh-faced, ‘inexperienced’ opponents,  the debates will favour him.

 However, for all the protocols and the preparation it would be unfortunate, as Lawson said,” if a close British general election were to be decided by a single cleverly worded put down or an unfortunate behavioral twitch on camera.”  But it could be.