Private schools heads have warned of a possible “brain drain” if Labour were to introduce its proposed 7 per cent cap on university admissions from the independent sector, with pupils opting to study abroad instead.

Chris Ramsey, co-chair of the Headmasters’ and Headmistresses’ Conference (HMC) universities committee, said some subjects like modern foreign languages could be severely impacted by such a cap.

News: DfE targets don't help state pupils, says private head

Background: Labour votes to abolish private schools

Labour policy: Scrapping Eton will become Labour policy, campaign says

“If you take a subject like MFL, our latest survey told us that 2,500 of our independently educated upper-sixth-formers were applying for modern languages courses," he said, speaking at the HMC annual conference in London.

"That’s one-fifth of the modern languages undergraduates that there are in the country.

"So if you just take that one subject, if only 7 per cent came in, where are the modern linguists going to come from, or are we just going to shrink the numbers of language students in our country?

"Also medicine: just over 7,000 applicants are from our schools – that’s a lower proportion than linguists but that’s still a lot of would-be medics.”

Sue Bishop, HMC’s director of external relations, said: “There are other universities all over the world, and you could end up with a brain drain.”

Mr Ramsey said there had been a slow but steady increase of students from independent schools choosing to go to universities overseas.

He added that the proportion of UK pupils at independent schools was higher than 7 per cent in post-16 education with just over 15 per cent of students aged 16-18 educated at independent schools, according to the most recent Independent Schools Council census.

Mr Ramsey said universities retaining their independence in admissions was paramount, and that contextual admissions should be carried out on an individual basis, rather than through a cap.

“Consistently, over the last three or four years the University of Oxford has said that of their most socially disadvantaged students – the bottom 10 per cent socially of their student intake – one-third have come through the independent sector,” he said.

“The cap presupposes the 7 per cent – and it’s higher than that at sixth form – it presupposes that the population is lined up from social advantage to disadvantage in a kind of long line…and that doesn’t bear scrutiny.

“A selective university would say, ‘We are selecting amongst high academic achievers and amongst those students, it is not 7 per cent who go to independent schools and 93 per cent who go to state school'.

“The independence of universities in their admission of students is enshrined in legislation that is centuries old, and I would say that as someone who is working in education, the freedom of university admissions is incredibly important, and the idea that the government would dictate the categories of people going to university is something that I think would be extremely damaging.”

Mike Buchanan, chair of the HMC, described the proposed cap as a “crude piece of political positioning”.

Labour has been contacted for comment.