"Calm down, dear" are three words David Cameron will hear much more of as future Coalition politics are played out.

A maxim in football is that one plays the ball and not the player and to do otherwise risks a penalty. Professional politicians are usually adept at avoiding this trap, and it was revealing to see David Cameron recently falling in. Not only was his “calm down dear “ exchange in Parliament with Angela Eagle patronising, but it revealed just one of the many examples of flawed thinking that pervade our lives.

When tackled the culprit usually evades responsibility by suggesting one does not have a sense of humour or one was taken out of context. That just compounds the felony through passing the blame on to the victim. The fact that it is a borrowed strap line from a Michael Winner advert, does not lessen the offence.

The “ad hominem” cannon – may have been the result of tiredness, carelessness and exasperation. It is usually when you have run out of lines of rationale argument and logical thinking. Whatever the reason – the result was unedifying to watch as were the reactions of neighbouring colleagues. Unfortunately, it pervades a great of daily life and just watch how a spat in the family or in customer-care goes down that line.

When political practitioners with their PR minders are exposed, it makes one realise that they are not as skilled in the communication arts as one imagines. As Coalition politics are played out in the years ahead, those three words are bound to be picked up by some creative copywriter. Watch this space. One thing is for sure, the advertising agency responsible for the original advert, must be relishing the fact that their product has suddenly found more legs.