The Treasury has announced that an EU exit ‘could leave households £4,300 a year worse off’. Since that only ‘could’ be the case, it could also not be the case, and given the accuracy of the Treasury’s prophecies for one year ahead, let alone 14, one wonders what odds the Treasury would offer on that outcome. The ancients had far better prophets.

One was the augur: he took the auspices to determine whether a course of action was wise or not (auis ‘bird’ + spicio ‘I observe’). Marking out an area of the sky, he watched for birds that flew into it. Those flying left to right were propitious, right to left unpropitious; eagles, vultures, and lammergeyers were especially good news.

The historian Livy made a character assert, ‘Who does not know that Rome was founded under auspices, and under auspices it conducts all its affairs, in war and in peace, at home and on the battlefield?’ And his history suggests an impressively accurate strike-rate from the professionals: after all, the Roman Empire did last for some 700 years.

Another was the haruspex, where haru– meant ‘guts’ (it is cognate with ‘hernia’). Whip a liver out of a sheep, and he would consult his liver chart to tell you whether the omens were good or bad.

Then there were the Sibylline books. The story was told that the Sibyl offered nine of them to Tarquinius Superbus (‘Arrogant’), the last king of Rome. He said the price was too high, but after she had burnt six of them he crumbled and paid the same price for the last three. Their contents were a closely guarded secret, and they were consulted only when disaster threatened, in order to avert it. Rumour has it that they found their way into Margaret Thatcher’s handbag, and she passed them on in sacred trust to the Mayor of London.

The fact is that the whole in-out debate is about the future, which no mere mortal can know. So: Treasury forecasts or Sibylline books? Given the age and track record of the Sibylline books, that’s where the clever money should go.