New immigration rules that mean migrants must be earning £35,000 or more to stay in the UK after six years will cost millions of pounds to the NHS and compromise patient safety, a nurses' union has warned.
The new measures, which apply to people from outside the European Economic Area (EEA) and are due to come into effect next year, will force thousands of nurses to return to their own country, the Royal College of Nursing (RCN) said.
It warned this will intensify the severe shortage of nurses in the UK and leave hospitals with nothing to show for the millions of pounds spent on recruiting them.
The RCN has calculated that up to 3,365 nurses currently working in the UK will potentially be affected, who will have cost the NHS £20.19 million in recruiting them.
It added that if international recruitment stays the same as it is now, by 2020 the number of nurses affected by the threshold will be 6,620, employed at a cost of £39.7 million.
And if workforce pressures force a higher rate of international recruitment, the number of nurses affected could be 29,755, costing more than £178.5 million to recruit.
The RCN is calling on the Government to reconsider the £35,000 salary threshold, add nurses to the list of occupations there is a shortage of, and to increase the number of UK nurse training places to reduce the over-reliance on overseas recruitment in the long term.
Dr Peter Carter, chief executive and general secretary of the RCN, said: "The immigration rules for health care workers will cause chaos for the NHS and other care services. At a time when demand is increasing, the UK is perversely making it harder to employ staff from overseas.
"The NHS has spent millions hiring nurses from overseas in order to provide safe staffing levels. These rules will mean that money has just been thrown down the drain.
"The UK will be sending away nurses who have contributed to the health service for six years. Losing their skills and knowledge and then having to start the cycle again and recruit to replace them is completely illogical."
"The only way for the UK to regain control over its own health service workforce is by training more nurses. 37,000 potential nursing students were turned away last year so there are people out there who want to embark on a nursing career."
A Home Office spokesman said: "As the Prime Minister has made clear, the Government wants to reduce the demand for migrant labour.
"We changed the settlement rules in 2011 to break the link between coming to work in the UK and staying here permanently. From 2016, non-EEA workers will need to earn at least £35,000 to settle in the UK for longer than six years.
"There are exemptions to this threshold for occupations where the UK has a shortage - but the independent Migration Advisory Committee recommended against adding nurses to the Shortage Occupation List after taking evidence from groups including the Royal College of Nursing.
"Employers have had since 2011 to prepare for the possibility their non-EEA workers may not meet the required salary threshold to remain in the UK permanently."