“In the long run,” Liam Byrne, the UK immigration minister, said this week, “our country and exchequer are better off with immigration rather than without it.”

In the short run, though, little can be said with certitude. Immigration to Britain is changing in every dimension, starting with magnitude. An eighth of the working-age population is now foreign-born – a rise of almost 70 per cent from a decade ago. The government has recently revised its net immigration figures upwards to 190,000 a year. Whereas old immigrants were, on average, better educated than natives, the new ones are less so.