So David Cameron, the UK prime minister, is now trusting that curbs on foreign students will help him achieve his election promise to cut immigration. Up to 100,000 annually will be barred from coming to Britain to study, in proposals published this week that restrict visas to "quality" students on degree-level courses.
It is a tough but necessary move if Mr Cameron is to meet his target of reducing long-term immigration from about 200,000 a year to "tens of thousands" by the next general election in five years.
In the first step of its plan, the government will cap from next April the total of the non-EU skilled and highly skilled intake at 21,700. This follows a temporary cap of 24,000 that has been in place since July. But, capitulating to business lobbies, the government is excluding the 22,500 workers moved to the UK by their companies every year. They will have to earn at least £40,000 (Dh232,000) a year to qualify and even those paid £24,000 or more can stay for up to a year.
However, this will make just a small dent and leave Mr Cameron struggling to fulfil his promise. Overseas students make more effective targets. Their numbers ballooned to more than 300,000 last year and they account for more than 50 per cent of non-EU migrants entering the UK.
Reducing their numbers is a colossal task, considering the billions of pounds that foreign students contribute to the economy. But it is not an insurmountable challenge. More than a quarter of those on student visas have no intention of attending courses, according to officials. Bogus colleges have also been on the rise. Since March last year, 56 of these so-called vocational and language colleges have had their licences revoked for "helping" students breach visa laws.
Damian Green, the immigration minister, launching the public consultation, says: "Too many students coming to study at below degree level have been coming here to live and work, rather than studying. We need to stop this abuse. This Government wants high-calibre students with the genuine desire to study to come to our country for temporary periods, and then return home."
Those coming to do "below-degree level" courses will be given visas for studies only at "highly trusted" colleges, Mr Green says. Students will have to go home after their course, ending the current scheme of allowing post-graduates to stay on for two years to look for a job that could lead to permanent settlement and then be joined by other family members.
With these curbs, together with a crackdown on family reunification, a job made easier by recent scandals of fake marriages, Mr Cameron would be well on his way to meeting his election commitment. Unfortunately, there are variables beyond his sway: the movements of EU citizens, who are free to live and compete in the UK, and the flow of Britons in and out of the country. In fact, net long-term immigration - the difference between people arriving and leaving the UK - rose to 215,000 for the year to March, thanks to more Britons coming home and fewer leaving because of sluggish economies worldwide.
The Office of Budget Responsibility (OBR) suggests that Mr Cameron's tinkering with the system will not make one iota of difference to net immigration. In its economic and financial outlook report last week, the OBR says: "At this stage, we judge that there is insufficient reason to change our average net migration assumption of 140,000 per year from 2010, which remains well below the net inflows of 198,000 seen in 2009."
But the OBR says this predicted fall is down to more relaxed restrictions on inward migration by other EU countries and potential migrants being put off by the slow economic recovery in the UK.
The government argues that the OBR's forecast takes into account only one part of immigration reform.
Mr Green says: "The impact of the government's limit on economic migration is accounted for within this reduction; however it takes no account of future proposals to limit immigration via the student or family routes."
Nevertheless, it is hard to see that such a respected economic body would make a public pronouncement without factoring in all the variables. However, Mr Cameron's determination should not be dismissed out of hand. His efforts might ultimately pay off. It is just a matter of how far and how soon.