Mr Gladstone had his wheelbarrow and tree-felling, Edward Heath his yacht and grand piano, Disraeli his romantic novels, the Duke of Wellington his military genius, Harold Macmillan his war record and voracious reading, and they say that David Lloyd George had a beautiful singing voice; but no British prime minister comes close to Winston Churchill in his tumultuous range of interests and applications: biographer, bricklayer, foodie, historian, journalist, orator, polo player, racehorse owner, soldier and artist. This last is what David Cannadine’s new book is about.