Immigrants must "add to the quality of life in Britain" to be let in, the Immigration Minister will say on Thursday.

Damian Green will say Britain does not need more middle managers or unskilled labour and only wants the "brightest and the best" migrants as the Government strives to be more selective in its immigration policies.

It is time to move away from the debate over numbers and ask "how we can benefit from immigration", he will claim.

The government has pledged to cut net migration from the current 242,000 to the "tens of thousands" last seen in the 1990s, with crackdowns on forced and sham marriages, bogus students and an annual cap on immigrants coming from outside the EU.

The Immigration Minister will say that bringing in any migrants who would be economically dependent on the state or who can "play no role in the life of this country" is unacceptable.

Instead "everyone who comes here must be selected to make a positive contribution", he will say.

And new specialist routes will be developed further to improve the visa system for short-term business visitors and entertainers, encouraging world-class performers to come to Britain.

While the inflow of students will be restricted, the government will also focus on ensuring they leave at the end of their visas, "reinforcing the notion that study is for a limited period."

Families wanting to settle in the UK will also face tougher requirements and the link between "coming to work and staying on permanently" will be broken.

In a speech at the Policy Exchange thinktank, Green is expected to say: "Whether you come here to work, study, or get married, we as a country are entitled to check that you will add to the quality of life in Britain."

He will go on: "Britain does not need more migrant middle managers, any more than it needs unskilled labour.

"We do need top of the range professionals, senior executives, technical specialists, entrepreneurs and exceptional artistic and scientific talent.

"One of the tasks for the future is shaping the system so that it allows us to be more precisely selective."

Outlining the principle of selectivity, he will say: "Importing economic dependency on the state is unacceptable.

"Bringing people to this country who can play no role in the life of this country is equally unacceptable."

On Sunday Green told The Sunday Times: "What we need is a system that...goes out to seek those people who are either going to create jobs or wealth or add to the high-level artistic and cultural aspirations we have.

"Getting the number down is the absolute key but what I am aiming at is fewer and better."

But Labour MP and shadow immigration minister Chris Bryant said there was a "massive gap" in Green's rhetoric and the reality.

"Tthe government is still weakening action on illegal immigration as we saw in the borders fiasco last summer.

"David Cameron pledged 'no ifs, no buts', net migration would be in the tens of thousands by the end of the Parliament. Yet the Minister today has again set out no workable proposals to deliver it."