Immigration remains one of the public’s prime concerns in the run-up to the general election, reinforced by the latest figures which show it to be running at a higher rate – nearly 300,000 a year – than at any time since the 2010 general election. This has gravely embarrassed the Conservative Party because it foolishly promised that by about this time the figure would be limited to below 100,000. But this is a problem for all the parties, none of which has a coherent and convincing set of proposals, nor even a clear picture of the problem. It is easy to say that the figure is too high, very difficult to suggest effective remedies.Even when its economy was in recession, Britain was a magnet that drew in workers from poorer parts abroad. With southern Europe still struggli