Overseeing Boris Johnson’s futuristic office, with its spectacular view of the increasingly culinary skyscape of the City of London with its Gherkins and Cheesegraters, is a bust of Pericles, distinctive in his helmet. It is no surprise that the Mayor should hold himself up to the gaze of the Athenian general and politician because he instituted the greatest programme of public works in the ancient world in Athens in the middle of the 5th century bc.