The analysis looked at what happened to the nursing workforce prior to and during efforts to boost the number of nurses by 50,000 under the previous Government.

Between April 2015 - June 2023, it finds nurses with more than 84 days of mental health related sickness absence in a three-month period were over six and a half times more likely to leave their role than those with 0-4 days of mental health sickness absence. Nurses with 5-14 days of mental health sickness absence were over twice as likely to leave than those with little-to-no mental health sickness absence.

The analysis also finds nurses at the top of NHS Band 7 were 25% more likely to leave than those at the bottom of Band 7. In addition, promotion is uneven between professions, with midwives moving up their pay bands faster than nurses.

Nurses from outside the UK or Europe are increasingly leaving the NHS, especially since 2021 (but overall, they are still less likely to leave than nurses from the UK). The analysis finds that in 2023/24, the risk of international nurses leaving was around 18% lower than UK nurses, compared with 36% lower in 2020/21.

Between January 2020 and June 2023, the South East of England saw the biggest net increase in nurses – by 7,145 (or 15.7%).

London had the lowest relative increase (10.1%, equivalent to 6,186 nurses), this was preceded by the highest growth in the previous comparable period (January 2016 - June 2019).

The North East and Yorkshire had low growth in the three-and-a-half year to June 2023 (10.2% or 5,894 nurses), which followed a net fall in the number of nurses (-1.3%) – suggesting that over a seven year period, this region has not made as much progress compared to other areas.

Nuffield Trust fellow, Lucina Rolewicz, said: ‘Policies aimed at nurses have often neglected retention, with not enough done to understand why they leave the NHS and what could encourage them to stay. As the Government works on its plans to bolster the nursing workforce, this new evidence gives clear reasons to focus on career progression opportunities, support with sickness absence and mental health, and issues particularly affecting overseas nurses' decisions to leave.'

Unison head of health Helga Pile said: ‘Clear career paths with pay progression to match are needed for nurses to continue working in the NHS, including those from overseas who're vital to the service.

‘Health workers across the NHS team have to know they're properly valued and have long-term career prospects. Better access to flexible working at more senior levels and improved support for health and well-being are essential.

‘For the NHS to deliver the quality care patients need, staff must also be paid fairly. Ministers must back the forthcoming structural talks with serious funding.'