Mary Dejevsky: We need to limit immigration – but this isn't the way to do it

It has been a long time in coming, but MPs have finally blown the gaff. The much-heralded "cap", they agree, will have only a negligible impact on immigration. When the policy was first announced, by the Conservatives before the election, I made some back-of-the-envelope calculations and wondered, in a rather desultory way, how soon the truth would out. A Commons Home Affairs Committee report published this week does the job. The "cap", it concludes, would apply to a bare 20 per cent of new arrivals. Nor would it reduce immigration by anything like that amount, unless every single application were rejected. The reality is that only one in five of all migrants will come into the category subject to the cap.

So what took everyone so long? Well, there was the election. With immigration high on the list of public concerns, few aspiring MPs were going to discredit a policy that seemed to have a chance of limiting the numbers. Labour candidates were in a particular bind, because their party was blamed for relaxing border controls; they did not want to seem "soft" on immigration. Only the Liberal Democrats risked a qualified welcome for migrants. Plus voters took a generally positive view of the proposed cap, as they did of the Labour government's points system. At last something quantifiable seemed to be in train. Even the very vocal objections from business were helpful in their way, reinforcing the idea that a cap would be an effective means of curbing immigration. The more loudly they shouted, people were allowed to construe, the more genuine their fear of being hurt.

It was in no one's interest to point out what became obvious to members of the Home Affairs Committee almost as soon as they started to hear evidence: the cap, as proposed, would apply only to a minority of a minority. Most of those coming to Britain are entitled, or encouraged, to do so. A proportion are already British citizens; they cannot be refused. The East and Central Europeans – those Poles there was all the fuss about – have a perfect right to work and settle here under European Union mobility rules.

If you take the figures for last year, by far the largest contingent (126,000) coming to Britain was made up of those on student visas, while the next largest (61,000) consisted of relatives of people already settled here. Neither of these groups would be subject to the cap, which applies only to those hoping to come to Britain from outside the EU and intending to work.

There is something else wrong with the cap as well, beyond the minute difference it stands to make. In enough cases to make compelling headlines, it threatens to make life difficult for precisely the wrong people. The points system has already begun to penalise individual invited guests as opposed to those who know how to play the system. In future, say employers, skilled workers, including much-needed scientists, will have every reason to go elsewhere.

Now I do not accept this argument completely. It is hard not to suspect that at least some employers, and those who lobby on their behalf, are crying wolf. If footballers can be exempted from the cap, I dare say some arrangement will be found for budding Nobel laureates. We are not talking big numbers here. And when employers complain about "skills gaps" and howl that their businesses will suffer if they cannot guarantee visas for non-EU specialists, you have to ask why they have not lobbied successive governments just as loudly about the quality of British education and why they have not done more to train the staff they already have. This applies, by the way, just as much to ethnic restaurants that until recently had the right to import young cooks (despite elevated rates of youth unemployment in the immediate vicinity) as it does to the likes of Barclays and IBM.

There is a case for the public sector to answer, too. Yes, it is convenient (and cheap) to pluck other countries' graduates off the peg, but why are we still luring so many doctors and nurses to our health service, for instance, from the countries that have funded their training and need them just as much as we do? And it is hard, or it should be, to believe claims that the cap will denude care homes of staff, when there are so many "new" Europeans still keen to work here and large lay-offs are expected elsewhere in the public sector. Dare I suggest that higher pay might reduce absence, foster reliability and generally improve productivity – more than paying for itself?

But if the Government's cap has no hope of meeting the unrealistic expectations invested in it – to reduce net immigration from almost 200,000 a year to the "tens of thousands" the Prime Minister has said he is aiming for – this does not mean that nothing can or should be done. Politically, the case for lower immigration has been pretty much accepted. Nor is the economic argument for an open door unimpeachable. Do we really have a skills shortage on a scale that free movement within the EU cannot address?

In trying to reduce immigration, however, the Government has to accept realities. The only new arrivals Britain has the power to restrict are those from outside the EU. But there is little point curbing a small and shrinking subcategory – those coming to work and already subject to the points system – while leaving the two far bigger groups untouched. This means, as the Commons report concluded, albeit with excessive caution, reviewing student visas and family reunions.

It defies logic to treat these two groups as sacrosanct. Universities are already pleading the necessity of attracting ever more high-paying students from abroad (China and India), yet higher fees for British students could help fill the gap. Nor need universities suffer disproportionately. Why not simply stop all visas for study at establishments other than universities – solving at a stroke the problem of bogus language schools. As for family reunions, despite stricter conditions for new spouses over the years, the provision of visas for relatives intending to settle here remains generous by international standards. The bar could be set higher than it is, preferably through an agreement negotiated to standardise the rules across the EU. MPs on the Home Affairs Committee say they will be considering these questions further, acknowledging their sensitivity. But if Mr Cameron really wants to cut net immigration to "tens of thousands", he should urge them to hurry up.

m.dejevsky@independent.co.uk