The press and police have been condemned for the way they fall on mere rumour and plaster it across the headlines, Sir Edward Heath’s ‘paedophilia’ being the latest example. The Roman historian Tacitus (c. ad 56–118) well understood the phenomenon.

‘Rumour is not always wrong; it is sometimes correct,’ Tacitus asserts, well aware that the occasional accurate rumour reinforced the potential credibility of the many false ones; and he understood why they played such a part in the world of the emperors, ‘where men’s throats were slit with a whisper’ (Juvenal).