Poor David Cameron. He pledged to reduce annual net migration from the current 240,000 to the "tens of thousands" and what happens? Net migration in 2010 was up by 21 per cent from 2009. In a way, he deserves the flak he'll get because this was a daft target that could only have been set by someone poorly-advised about the nature of immigration. And the target allows success to be presented as failure.
The inflow to Britain has stayed steady (see graph below), but the number emigrating from Britain has fallen. This is a compliment to Cameron: the most sincere vote people can make is with their feet. And in our globalised world, countries have to compete for people. Britain is as attractive as ever it was to immigrants, and more natives are staying put.
Cameron should only ever have pledged to stem the inflow. Governments of free countries can't stop people emigrating, so the net figure, ie the inflow minus the outflow, is not something he could or should have given a pledge on. In my view, Britain's immigration inflow is driven primarily by a demand for migrant labour (foreign nationals account for almost the entire employment rise under Cameron so far). This can only be changed by radical labour market reform (tax, regulation etc), which I don't expect to happen. So I'd say Cameron has a snowball's chance in hell of meeting his target. Today's figures will be the first of many over the next four years making that point.