In their thirst for evidence on this issue, commentators seized on the recent report by the Census Bureau, which found that average household income rose by 5.
However, signs are emerging of significant job loss and of growing shortages of productive employment, which are aggravated by the reduction of emigration flows.
The possibility of emigration may even have beneficial effects on those who choose to stay, by giving people in poor countries an incentive to invest in education.
Data released in November showed 577,000 immigrants arrived in Britain in 2007, 14,000 fewer than the year before (although emigration fell faster, lifting net migration).