Brown: Immigrants should make "an additional contribution over and above tax"
Gordon Brown has promised to "tighten" the UK's immigration rules by reducing the number of professions that can recruit from outside Europe.
The prime minister said net migration was already being cut and that these changes would ensure this continues while maintaining "flexibility".
He also promised to make it harder for illegal workers to enter the UK by obtaining student visas.
But the Conservatives dismissed Mr Brown's proposals as "hollow".
The prime minister's speech, in west London, came amid criticism that immigration policy is ineffective and predictions that the UK's population is set to reach 70 million.
Home Secretary Alan Johnson recently admitted that the government had taken "a long time" to deal properly with the issue.
Mr Brown defended the government's points-based system for deciding which migrants from outside the European Economic Area - made up of the EU states plus Iceland, Liechtenstein and Norway - and Switzerland should be accepted.
He argued that it had contributed to a 44% fall in inward migration over the past year.
Mr Brown said the importance of "shortage" professions would be looked at in the near future.
People want to be assured that newcomers will accept the responsibilities as well as the rights that come with living here
"We will remove more occupations and therefore thousands more posts from the list of those eligible for entry under the points-based system," he said.
Engineers, skilled chefs and care workers could be among the professions affected.
Mr Brown announced a review of student visas, which will consider whether they should be granted only to foreign students on degree and postgraduate courses.
Visas would be stopped for those seeking to take shorter courses leading to lower-level qualifications, to clamp down on people using these as an excuse to enter the UK before disappearing into illegal work.
Addressing the wider immigration debate, Mr Brown added: "I have never agreed with the lazy elitism that dismisses immigration as an issue, or portrays anyone who has concerns about immigration as a racist. Immigration is not an issue for fringe parties nor a taboo subject.
"It is a question at the heart of our politics, a question about what it means to be British; about the values we hold dear and the responsibilities we expect of those coming into our country; about how we secure the skills we need to compete in the global economy; about how we preserve and strengthen our communities."
He said: "If the main effect of immigration on your life is to make it easier to find a plumber, or when you see doctors and nurses from overseas in your local hospital, you are likely to think more about the benefits of migration than the possible costs.
"But people want to be assured that newcomers will accept the responsibilities as well as the rights that come with living here - obeying the law, speaking English, and making a contribution."
The UK was a "something-for-something, nothing-for-nothing" society, Mr Brown said, urging immigrants to live up to their responsibilities.
He advocated a "tough but fair approach" to immigration, maintaining the "flexibility" needed by employers.
More needed to be done to ensure that people already living in the UK with low skills and poor job prospects were helped into work.
In an interview with the Daily Mail, Mr Brown said he did not believe Britain's population would reach 70 million, as some projections suggest.
For the Conservatives, shadow home secretary Chris Grayling said: "Gordon Brown's speech had a completely hollow ring to it.
"This is the government that tried to cover up a deliberate policy of increasing immigration and the prime minister's comments show that he has no idea about how to deal with the whole question of immigration now."
Liberal Democrat home affairs spokesman Chris Huhne said: "Gordon Brown is attempting to shut the stable door long after the horse has bolted.
"His government's catastrophic mismanagement of the system has undermined this country's liberal attitude towards immigration."
Sir Andrew Green, chairman of the Migrationwatch campaign group, said the prime minister's measures were "trivial" and that Mr Brown was "in deep denial" on the issue of immigration.
The co-chairmen of Parliament's cross-party group for balanced migration, Labour MP Frank Field and Conservative MP Nicholas Soames, said: "While the government is right to split economic migration from permanent settlement, it is clear that the prime minister misses the big picture.
"The points-based system has no limit, affects just 20% of immigration and will not stop the UK's population hitting 70 million in 2029."
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