The fantastic element in all this is that these people were migrating north. As a thermophile, I am appalled that anyone would leave the Mediterranean islands and Iberia for Ireland, Wales, Denmark.

After thirty years, I am still chuckling over a joke Alastair Cook made in one of his introductions to the I, Claudius series for its broadcast on US TV. He noted that the Scots occasionally gloat about turning back the Romans. He read a quote from someone about how, having mastered all the lands of the balmy Mediterranean the Romans arrived in Scotland, observed savages chasing deer across the moors in a blue mist and, finding nothing to appeal to them, just turned back.