Aside from the hair, Boris Johnson and Alan Yarrow have a good deal in common.

The Mayor and the Lord Mayor of London are both robust defenders of the capital as an international financial centre. They celebrate the 21st-century City - a high-tech, polyglot powerhouse. But the old Etonian and the old Harrovian also share a more conservative view that some of the old ways were better. And each has a refreshing habit of speaking his mind.