Boris Johnson has indicated that Government departments and agencies will get a greater say in controlling immigration numbers for their industries after Brexit.

The announcement comes hours after the Home Office rejected Nicola Sturgeon's proposal that the Scottish Government will get a greater say in controlling immigration numbers for their industries after Brexit.

The Prime Minister also defended his plan to fast-track entry to the UK for scientists, researchers and mathematicians after it was pointed out that the current cap was never met.

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On Monday, Johnson launched his new "Global Talent" visa to replace the Tier 1 (Exceptional Talent) from February 20.

The National: Boris Johnson

Unlike the current scheme, it will not have an upper limit of applicants and will accept endorsements from a wider pool of organisations.

It will be managed by the UK Research and Innovation quango to enable UK-based research projects that have received recognised prestigious grants and awards to recruit global talent.

In an interview at the King's College London Mathematics School, Johnson hinted the model could be extended to other bodies overseeing industries relying on low-skilled labour.

"What we want to have is a system that is responsive to the needs of the UK economy in all its dimensions," he replied when asked about the possibility.

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"So, yes, there will be sectors like agriculture or retail, hospitality, whatever, that do need to continue to attract low-skilled workers, but we want to make sure that's done very much on the basis of jobs they have to come to here in the UK."

But questions have been raised over the "Global Talent" scheme because the 2,000-applicant cap that the previous visa system had was never met.

The PM responded: "There are more and more people who want to come and study in the UK and work in the UK and what we are saying to the world is as we come out of the EU we are going to be open not just to talent from the EU - we will be, of course - but we want to attract mathematical and scientific talent from around the world.

"The UK is the number one capital for research for universities and we want to really intensify our lead."

During the college visit, a perplexed PM was explained mathematical problems by A-level students and wildly operated a robot on a lab bench.

The new scheme will enable UK-based research projects that have received recognised prestigious grants and awards to recruit global talent.

Applicants will not need a job offer before arriving in the UK under the visa and it will provide an accelerated path to settlement for all scientists and researchers who are endorsed on the route.

The National: Boris Johnson

The Government also announced a £300 million investment to fund experimental and imaginative mathematical sciences research over the next five years.

It will double funding for new PhDs and boost the number of maths fellowships and research projects.

The announcement was welcomed by the Royal Society, whose president Venki Ramakrishnan said it "sends out a positive message that the UK is committed to remaining open to overseas science talent".

And Professor Julia Buckingham, president of Universities UK, said the visa is a "positive step towards" making the UK a "magnet" for global science and research talent.

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She added: "The visa route will help to ensure that universities can attract the brightest scientists and researchers to the UK with minimal barriers."

However, Liberal Democrat home affairs spokeswoman Christine Jardine said the announcement was "nothing more than a marketing gimmick".

"Boris Johnson is showing that he fundamentally doesn't understand what makes our science sector so successful. Changing the name of a visa and removing a cap that's never been hit is not a serious plan," she said.