The Conservatives’ pledge to bring down net migration was always wrong-headed. Now we know it won’t be met

The promise to reduce net migration to the “tens of thousands” was a foolish one for the Conservative Party to make, and so, yesterday, it was proved. David Cameron was warned before the 2010 election that the pledge made no sense, arithmetically, politically or economically. Arithmetically, it made no sense because tens of thousands can be added up to make millions. That problem at least was solved easily, because the Tory leader accepted the implication and stated his intention to bring net migration to below 100,000 a year.

Politically, the promise made no sense because Mr Cameron was setting a target, despite his insistence in other areas of public policy that “top-down targets” distorted priorities and produced perverse incentives. In this case, he was setting a target that simply could not be delivered. The 100,000-a-year figure is the difference between two large numbers, of immigrants and emigrants – both of them estimates because we do not count people in and out of the country, and neither of them controlled by the Government. He was, therefore, failing the two cardinal rules of politics, the first of which is never to promise what you cannot deliver, and the second of which is always to manage expectations.

Worse, to the extent that the target figure can be predicted, even if it cannot be controlled, it was always likely to go up by the time of the election. The economy is the main influence on both emigration and immigration. Emigration increased in 2008 and the first half of 2009 as unemployment rose and people sought to improve themselves in other countries. Since then, and as the economy has slowly and fitfully recovered, the number of people leaving has fallen back.

Interestingly, immigration did not slow down until late 2011. It continued to fall until the middle of last year, since when economic growth has been strong and the number of arrivals started to rise again. Hence yesterday’s figures, for the year to September, which show net annual migration, having fallen to 154,000 the year before, now running at 212,000.

This brings us to the economic reason that Mr Cameron’s pledge was unwise. Immigration is both a symptom of economic success and a cause of further prosperity. This is a difficult argument to make, politically, because it requires the courage to tell people on low incomes to disregard what they experience as the effects of immigration, which they think holds down wages or keeps them out of work altogether. In fact, immigration stimulates economic activity and makes us better off.

Because the free movement of labour may come at a cost to social cohesion, a balance does need to be struck. Indeed, this newspaper supports many of the measures taken by the Coalition to tighten the control of family unions, to prevent bogus students and to stop fraudulent asylum claims. But the Government is not doing enough to attract the best of the world’s students and wealth-creating entrepreneurs. The free movement of workers within the European Union is also, as Angela Merkel said yesterday, one of our greatest achievements that benefits us all. Unfortunately, the main effect of Mr Cameron’s foolish pledge is to make it harder to persuade people that she is right.