Hospital services are increasingly reliant on doctors and nurses recruited from outside the UK and the EU, workforce data reveals.

According to research by the BBC Shared Data Unit, the London North West University Healthcare NHS Trust, which includes Northwick Park Hospital, saw an 11.9 per cent increase in the share of medical staff joining from outside the UK and EU between 2015 and 2021.

In the same period, the trust saw a 6.7pc decrease in the share of UK medical staff joining the services.

While the government said overseas recruitment has always been part of the long-term strategy, critics have warned this is an unsustainable way of recruiting in the long term.

Patricia Marquis, director for England of the Royal College of Nursing (RCN), said ministers must do more to reduce the "disproportionate reliance" on international recruits.

She said: “Our internationally-recruited nurses are, and have always been, invaluable to our health and care services, but ministers must do more to boost the domestic recruitment of nursing staff.

“One of the simplest ways to recruit and retain staff is to pay them fairly.”

However, while the NHS is recruiting more international doctors and nurses, it also faces challenges of retaining them, which the British Medical Association put down to “punishing workloads” and the cost of visas.

The share of international medical staff leaving the Brent-based trust increased by 9.8pc between 2015 and 2021 while the share of UK doctors and nurses leaving decreased by 10.6pc.

The share of EU medical staff joining the trust decreased by 5.2pc while there was a 0.8pc increase in EU doctors and nurses leaving the trust during the same period.

The findings are broadly consistent with the wider national picture. The share of homegrown doctors joining English NHS services decreased by 11pc between 2015 and 2021 and the share of UK nurses fell by 13pc.

During the same period the share of international doctors joining English health services rose by 16pc while the share of international nurses rose by 27pc.

The Department for Health and Social Care said the government has funded an additional 1,500 undergraduate medical school places and pointed to a 34pc rise in the number of doctors since 2010.

Kate Shoesmith, deputy CEO at the Recruitment and Employment Confederation (REC), said staff shortages in the NHS are “the worst they had ever been”.