Sue Ferns, Prospect's senior deputy general secretary, responded:

“The prime minister talks about making it easier for scientists to come to the UK, but his No Deal Brexit policy remains the biggest risk to science in the UK.

“Science is an inherently collaborative enterprise, which means that maintaining workforce mobility is absolutely essential, both for leading experts and for the researchers, lab assistants and others who are vital parts of research teams.

“The government needs to urgently clarify these new rules on migration and guarantee the funding needed to maintain the UK’s position as a world leader in science.

“The current path to a no deal exit could be catastrophic for UK science and deeply damaging to our ability to compete internationally.”