Twelve ingredients make up the recipe for a great prime minister

Many of the criticisms levelled at Boris Johnson, and at his predecessors, imply that if only a politician as upright and intelligent as the author of the attack were to enter No 10, we would have a perfect prime minister. But has such a paragon ever actually reached the top of the greasy pole? While writing a volume of brief lives of all 55 holders of the office — starting with Sir Robert Walpole, who took office 300 years ago next Saturday — I took to jotting down some of the qualities which make for success in the role:

1. Courage.

2. Luck.

3. Hunger for power.

4, Eloquence, including the ability to think on your feet in the Commons. The five PMs who never