The first thing to do in any discussion about the impact of migration on employment is to disregard MigrationWatch. It brought out a report on Monday noting the correlation between youth unemployment and immigration (finding that, between 2004 and 2011, unemployment among the young had risen from 575,000 to over a million, while 600,000 eastern Europeans had entered the labour force). Matt Cavanagh from the Institute for Public Policy Research took this apart immediately – and if you think that was quick work, bear in mind that MigrationWatch has brought out this report before, 18 months ago, and the flaws in it have already been uncovered. It’s reheating material that has already been discredited in the hope that the crisis of youth unemployment will leave us clutching at any explanation. Next it will blame Spanish bluebells, and grey squirrels, and witches.