Home Secretary Theresa May's plans to cut the number of foreign students coming to Britain will cost the economy £2.4 billion, figures have shown.
The crackdown on bogus students and colleges is part of David Cameron's drive to bring net immigration down from more than 200,000 to tens of thousands annually by 2015.
But the reforms will cost the UK £2.4 billion, an impact assessment released by the Home Office showed.
Costs of £3.6 billion will include £2 billion from a "reduced output from students and their dependants" who will no longer be able to come to the UK and from tighter control of foreign students' ability to work in the UK, the assessment said.
A further £170 million cost will come in the loss of student tuition fees to institutions, while the reduced output from post-study workers will cost £1.2 billion. The UK Border Agency is also expected to see a £160 million loss in income from fees.
But the moves will also bring benefits of £1.1 billion.
Overall, the assessment said the "best estimate" was that the reforms would cost £2.4 billion, but this could be up to £3.6 billion in the worse case scenario.
Immigration Minister Damian Green said: "We are radically reforming the immigration system to tackle abuse and bring net migration down to sustainable levels. These changes to the student visa system will create a system where every student coming to the UK attends a legitimate course at a legitimate institution."
The impact assessment also showed there will be 273,000 fewer student visa grants over the full five years of the parliament, leading to a fall in net migration of about 232,000.
A UKBA spokesman said: "These proposals will lead to savings of £1.1 billion, most of which will benefit our public services. It may be there will be even greater benefits as it is not unreasonable to assume that jobs not taken by migrant students will instead be taken up by British workers."
