The government was right to tighten rules for those who might become a drain on the state, he said, but warned “It’s crazy that we should be losing India’s top talent and the global leaders of the future to Australia and the United States.”

“The most important thing is academic freedom — if people are genuine students and genuinely desire to learn and contribute to the economy there should be a system which allows them to travel from one major centre of learning to another, and that’s what we’re trying to achieve,” he told students and academics at Delhi’s Amity University which announced it was establishing a new 15,000 student campus in London.

In an interview with The Telegraph, he said changes in visa regulations, to limit the amount of time students can remain in Britain to work, had caused a negative impression. “Indians are being put off. It’s a bit of perception [but] too many people have had difficulty. A lot of people raise it with me, students and businessmen too. They need to stay and take up employment more speedily [and for a longer period]. But generally their applications need to be processed faster and we need to be more sympathetic and not shutting off a major source of investment in our education,” he said.

^{During Boris Johnson’s visit to Delhi he handed over the London 2012 Olympic cauldron petals to Indian Olympians (PA)}

Until last April, Indian students studying at a British educational establishment were automatically allowed to stay and work for two years after their course ended. But concerns that too many were coming to Britain for dubious courses and staying for low paid jobs led to new rules which allowed longer stays after course completion but only for those with ‘graduate level jobs’ on salaries higher than £20,000. These students can stay for three years and can extend for a further six years if they meet the salary requirements.

Mr Johnson told the Home Secretary it was necessary to “shift the debate on student visas away from numerical targets and squarely onto policy based on promoting jobs and growth in the UK. This is why I am supporting a growing, cross-party consensus on removing students from the Government’s net migration target,” he said. He is also calling for a ‘Migration Advisory committee’ to conduct a cost-benefit study of international students to the British economy and new measures to protect foreign students against being repatriated if their college loses its license to recruit overseas.

His comments were welcomed by the British Business Group in India which has raised concerns about the changes. “No one can argue that bogus institutions or students should go unchecked. But it is vital for the UK’s prosperity that we are seen as a preferred education partnert for good and genuine Indian students. Our image as an attractive education destination has clearly suffered recently in India,” said Mark Runacres, head of the British Business Group and an educational consultancy.

British officials said the number of Indian undergraduate and postgraduate students had doubled from 2007 to 2011, but it is not yet known whether the new rules have affected those wanting to study in the United Kingdom.

Foreign students: countries sending the most students to the UK (in pictures)