They are three of the most devastating words in English literature. Their force comes only partly from the fact that Antony - who will shortly end his own life by the pleasantly traditional Roman method of falling on his sword - is misinformed: Cleopatra is not dead but, teasingly, alive. What makes the phrase so shocking is the tense: past historic, as if a vast expanse of time has elapsed since Cleopatra’s death. And that is just what Shakespeare intends: for Antony, the post-Cleopatra epoch is an entirely different world, in which life is no longer worth living. We are stunned by the enormity of the concept as much as by the enormity of the error.

Tenses matter, which is why their misuse grates so dreadfully. British telephone subscribers who dial an engaged number are greeted by a recorded message which begins: ‘The number you dialled is busy.’ The number I dialled when? Yesterday? Last week? For the number I have just dialled is, precisely, the number I have dialled: perfect, not past historic. Of course, it helps not a bit that British Telecom compounds the offence by saying that the number is ‘busy’, an intelligible though ridiculous Americanism. Busy doing what, we may wonder: is it careering about the place in a frantic hurry or sitting still, doing some concentrated work? ‘Engaged’, on the other hand, is exactly right, the sign on the bathroom or lavatory door which is the opposite of ‘Vacant’: a barrier which, ...