A 39-page introduction, followed by a notice announcing the reigns of William III and Anne were in the press was all that appeared of John Wilkes’ promised history of England. He was scarcely alone. Unfinished historical works include a history of Europe since 1598 by Bolingbroke, Burke’s Essay towards an Abridgement of the English History, Robertson’s history of British and Portuguese colonisation of the Americas, and Paine’s History of the American Revolution.

There have been many reasons: death, politics, indolence, publication by others or a decision to move to other topics. My Imperial Legacies fell foul of a squeamish publisher who felt he would not be able to ‘look many of my dearest friends in the eye.’ Fortunately, another publisher lacked such preconceptions. Similarly, my History of the British Isles found a new publisher because I couldn’t stimulate a zeal for Irish nationalism, though in both cases I got to keep the advances.

Then there are books you decline to write. I turned down a history of projectiles in warfare (not interested), the War of the Spanish Succession (nothing new to say), and a history of sex (beyond me, but my excuse was that only a woman or a homosexual male would be sufficiently politically correct).

I lost enthusiasm for a large-scale world in the 18th century because of the scale of the secondary reading. I had all the notes for my planned history of British foreign policy in the War of the Polish Succession, with a particular emphasis on 1735 (not addressed by Paul Vaucher; Plumb, of course, was a joker), but felt it would only interest a crowd in a telephone kiosk.

Do I ever regret the books I might have written? Only fleetingly, because the pressure of the present task is too great. Interviewed in 1995 for the Exeter chair, I was asked what my plan was for five years’ time. My reply that I had none as I might be knocked down by a bus that afternoon was dismissed as ridiculous, but that was how I conducted my life. There is no point leaving unfinished works while striving for transient would-be perfection. Write good books, to time and the agreed length. Leave the “perfect” definitive work to unfinished dreamers, or should I say poseurs.