Michelle Obama once said that she used to fear that the presidency of the United States would change her husband, but as she comes to the end of her time in the White House, she has realised that power doesn’t change who you are — “it reveals who you are”. Leadership is like an x-ray machine that reaches into the soul.

As Theresa May is finding, there is no job in Britain that exposes the holder more than prime minister. Other politicians can obfuscate, prevaricate or pass the buck, but public opinion and the media always seek out the resident of No 10. The premiership is a test of character as well as of intellectual capability, and so ambiguity can be as revealing as clarity