Last week it was suggested that the questions asked of London mayor Sadiq Khan had nothing to do with racism, but more with multiculturalism. As St Ambrose could have said, ‘If you live in Rome, live in the Roman way; if elsewhere, as they do there.’

Until the large-scale irruption of Germanic tribes fleeing the Huns in the 4th century AD, eventually ending the Roman empire in the West, Romans had been fairly relaxed about immigrants, temporary or permanent.