Leading GPs have renewed calls for post-Brexit assurances for European doctors after figures revealed that without these medics, 3.5 million patients could be left without a family doctor.
Across the UK, there are 2,137 GPs from Europe, the Royal College of GPs (RCGP) said.
These family doctors collectively care for 3,456,481 patients, the college estimated.
EU doctors make up 5% of the GP workforce in England, 11% in Northern Ireland and 4% in Scotland and Wales.
Without them, millions of patients could be left without a GP, the RCGP said.
Losing these GPs would be "disastrous", RCGP chairwoman Professor Helen Stokes-Lampard said.
"We desperately need thousands more GPs right across the UK, and in England we have been promised 5,000 more by 2020, but these figures indicate that we risk losing well over 2,000 family doctors from the NHS if their position is not secured as part of Brexit negotiations, and that is just not safe or acceptable," she said
"EU workers in general practice, and the NHS as a whole, play a vital role in ensuring that care is delivered free at the point of need for anyone who needs it.
"Losing this skill and experience would be disastrous for the sustainability of our health service and our ability to deliver the care our patients need.
"It is essential that EU workers in general practice and across the health service continue to feel welcome, valued, and that their future is secure.
"We have a severe shortage of GPs and other practice staff across the UK and we are very grateful for the work that doctors from overseas are currently doing to deliver excellent patient care and support us to meet the demands of our ageing and growing population.
"Ensuring that the status of EU GPs working in the NHS is secure as part of Brexit negotiations is one of the college's Six Steps for Safer General Practice; our manifesto for the next government."