What is the most important trait in a good Prime Minister?

Honesty? Intelligence? The ability to stick to your principles? If a new poll of MPs is to be believed, the answer is none of the above. The poll, which was conducted by the University of London, revealed that three-quarters of the MPs who took part believe the most important trait in a PM is decisiveness.

But is that true? There can be no doubt it is one of the qualities needed, but putting it top led to Margaret Thatcher being rated as the most successful post-war PM.

For the avoidance of doubt, it was not just Tories who took part (the MPs were evenly spread between the parties) but, even so, using decisiveness to rate Lady Thatcher as the best PM is problematic.

She certainly proved able to make decisions, but the problem is they were often the wrong decisions, such as introducing the poll tax. Perhaps a better word than decisive would be divisive.

As for David Cameron, he was not included in the poll so we do not know what the MPs made of his qualifications for the job. Perhaps, for him, that was a lucky escape.