The Government has been accused of making thousands of skilled migrants destitute by luring them to Britain and then changing the rules that allowed them to work here.

About 20,000 people, many of them entrepreneurs, scientists and IT specialists, have come to Britain under the highly skilled migrants programme since it was brought in four years ago. They pledged to make Britain their main home and were offered permanent residence after four years.

But under changes announced in November and applied retrospectively they must now apply to extend their visas under different criteria, which put greater emphasis on high earnings and education and less on work experience. It is thought that about 6,000 fail under the new rules.

The Government insists that it had to make the changes to stop abuse of the programme and to ensure that it attracts the right people.

But MPs who have been deluged with complaints say that the changes defy natural justice and are economically self-defeating, forcing skilled migrants in well-paid jobs to leave the country.

Many of these people sold businesses and houses in their home countries before coming to Britain, and some must now take their children out of schools and universities here.

The migrants have set up at least two campaign groups and launched three judicial reviews. A protest is planned outside Parliament this month.

Mikhail Spivakov, a molecular biologist from Russia, who works for the Medical Research Council and has set up Voice of Britain’s Skilled Immigrants, said: “We respect Britain’s rights to change its immigration laws, but bringing people in under one set of rules, using their skills and abilities, then changing the rules at short notice to get rid of these people is unfair.”

Many of the immigrants say they regret coming to Britain. Padmanabhan Badrinath, an Indian-born public health consultant, said: “By applying changes to the immigration rules retrospectively, the Government has shattered the dreams of thousands of skilled migrants. If I had known the Government would change the rules midway I would not have come here.”

Amit Kapadia, also from India, founded the HSMP 2006 campaign group, representing 1,200 other migrants. He has fallen foul of the rule changes because his earnings are less than the £35,000 threshold. Mr Kapadia, who has an MBA from the University of Strathclyde, said: “Why should I live with this uncertainty and unpredictability?”

Damian Green, the Conservative spokesman on immigration, said: “Thousands of people who came in good faith with the skills we need are being sent back again. As a country, we have broken faith with people we want. The Government has acted stupidly, going against the economic interests of the country and natural justice.”

Andrew Dismore, Labour MP for Hendon, said: “There is a strong objection to retrospective application of the rules — the decision that the new rules will apply to people who have already come to the UK expecting to be able to settle here permanently after four years. That is utterly unfair.”

The Immigration Law Practitioners’ Association has been involved in a fierce exchange of letters with Liam Byrne, the Immigration Minister. The Home Office has created transitional arrangements to help migrants to transfer to other visas, such as ordinary work permits.

In one letter, seen by The Times, Mr Byrne insisted: “I am satisfied that these changes strike the correct balance between the need to address the needs of the highly skilled migrant programme applicants with the need to carry out policies which are in the interests of the UK.” It was meant to bring the sort of opportunities of which his family had always dreamed. Instead, joining the highly skilled migrant programme has brought Chanbika Bhatta to the brink of homelessness and bankruptcy in just a year (Anthony Browne writes).

“I had the pick of life, but now I am at the bottom,” he told The Times. “Within a year, everything has collapsed. It is intolerable for me.”

In Nepal, Mr Bhatta was a college principal and president of the national association of English teachers, with a decent standard of life and a good home. Rather than cruise on to retirement, he decided to put his children first. He wanted his two sons to attend university in Britain, so, at 51, he moved to Britain, having been accepted by the programme.

Mr Bhatta signed a deal with the Home Office pledging to make Britain his permanent home. He took up a job in education and also provided private tutoring.

A year later the Home Office changed the rules and when Mr Bhatta applied to renew his visa, last month he was rejected. He is considered too old, and his income too low.

“I didn’t qualify under the new criteria,” he said. “We had a treaty with the Home Office — there has been a one-sided breach of the treaty.” He said that that he had no alternative but to return to Nepal, although he will not return to his previous lifestyle.

“When I go back I will be jobless — I won’t get back my old job. It is social and political humiliation. I had a good property before in Nepal, but I will be returning homeless. I had a good amount of money, but I will be returning bankrupt.”

His elder son is at university in Aberdeen, but without the right to residence the fees increase to the international rate of £12,000 a year.

“He has to stop his education,” said Mr Bhatta. “It’s injustice for him as well.”

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