More than 6,000 visa applications for highly skilled workers like scientists, IT specialists and doctors with job offers in the UK were refused because of a Government-imposed cap on numbers, it has been revealed.
The refusals came between December 2017 and March 2018 and were the result of an annual limit of 20,700 so-called Tier 2 visas introduced in 2011 while Theresa May was home secretary.
It is understood that the limit had been breached only once before, in 2015, when 66 engineering roles were refused.
The Campaign for Science and Engineering (CaSE), which obtained the figures from a Freedom of Information request to the Home Office, said the "arbitrary" cap was leaving thousands of vital roles unfilled and damaging productivity, public services, business confidence and the UK's international reputation.
The figures emerged as the House of Commons Science and Technology Committee announced plans to develop its own proposals for new immigration rules for scientists after Brexit.
Among the 6,080 refusals over the four-month period, 1,518 related to doctor posts and 361 to other healthcare professional roles, 1,226 to jobs in IT and technology, 392 engineering roles, 197 teachers, 1,814 professional services and 572 to other professions.
It is possible that some of the refusals related to the same individuals, as employers are able to resubmit applications each month.
CaSE executive director Sarah Main said: "These figures show the scale of the problem and the urgency to find a solution.
"Across the country, businesses and public services are being blocked at the last hurdle from recruiting the people they need, including in health, engineering and tech, due to the visa cap. This leaves employers frustrated and the public poorly served."
CaSE has called on the Government to exempt PhD-level roles and jobs on the shortage occupation list from the cap on Tier 2 visas.
Dr Main said: "The cap is beginning to cause damage and it needs to be addressed quickly. In the immediate term, shortage and PhD level roles should be made exempt from the cap. This would be in line with the priority already afforded to these roles and would create the headroom for other vital roles.
"In the long term, an immigration system for a Global Britain that supports research and innovation should not feature a cap on the international specialists we want to attract."