New figures from the Nursing and Midwifery Council show that for the first time in recent history more midwives and nurses are leaving the register than are joining, with homegrown UK nurses leaving in the largest numbers.
Between 2016 and 2017, 20 per cent more people left the register than joined it, and among those first registered in the UK, the figure was 45 per cent.
The Royal College of Nursing, and the Royal College of Midwives, which says the country is already 3,500 midwives short, called on the Government to scrap the pay cap as a matter of urgency.
The data shows following yearly rises since 2013 in numbers on the register, there was a drop in 2016/17 of 1,783 to 690,773. From April to May this year, there has been a more dramatic fall, with a further 3,264 workers leaving the profession.
The overall number of leavers - including UK, overseas and EU registrants - has increased from 23,087 in 2012/13 to 34,941 in 2016/17.
Leavers among those first registered in the UK - who make up 85 per cent of the entire register - jumped from 19,819 in 2012/2013 to 29,434 in 2016/2017.
Saffron Cordery, from NHS Providers, which represents hospital trusts, said: “This goes beyond the concerns over Brexit - worrying though they are.
“The reduction in numbers is most pronounced among UK registrants.
“And it is particularly disappointing to see so many of our younger nurses and midwives choosing to leave.”
She said a new staff retention programme will offer support to those NHS trusts with the highest leaving rates, but added: “However, until we address the underlying issues driving retention problems, including the pay cap and the unsustainable workplace pressures, these approaches will only have a limited impact.”
The data also shows that the number of EU workers (who make up five per cent of the register) leaving has increased from 1,173 in 2012/2013 to 3,081 in 2016/2017.
It also showed a rise in the number of nurses and midwives below retirement age quitting.
In 2016/17, over a fifth (7,760) were aged 56 to 60, while around a sixth (4,789) were aged 51 to 55 - almost double the figure for 2012/13.
The number of leavers in the 21 to 30 age group also almost doubled from 1,510 to 2,901.
Rising numbers of staff left for similar jobs abroad, with 4,153 “verification requests” made in 2016/17.
A survey showed of those not retiring, 44 per cent cited working conditions (for example staffing levels and workload), while 28 per cent cited a change in personal circumstances (such as ill health) and 27 per cent disillusionment with the quality of care to patients.
Other reasons included leaving the UK (18 per cent) and poor pay and benefits (16 per cent).
The Department of Health said there were more than 13,000 more nurses on wards since May 2010 and 52,000 in training.