One London hospital nurse said she had clocked up 1,500 hours of overtime since Covid-19 arrived in Britain — an extra four hours for every day in the year. A worn-out colleague said she was leaving a highly skilled job in intensive care for the relative respite of the vaccination campaign.

“I’ve made a decision to jump ship and do what’s best for me and preserve my own health,” she said.

Some nurses are leaving the NHS altogether, especially EU citizens who have returned to their home countries in recent weeks: post-Brexit anxiety combining with another wave of coronavirus to deliver a significant blow to the UK’s health service.

The virus is taking a relentless toll — 30 per cent of all the Covid-19 admissions to English hospitals since the start of the pandemic happened last month, NHS England said on Thursday. Interviews with staff from numerous hospitals showed how deeply it is affecting nurses, provoking a crisis of morale that threatens to endure beyond any retreat of the disease.

“We have given absolutely everything,” said Stuart Tuckwood, a critical care nurse and national nursing officer at Unison, the UK trade union. He said there was a growing clamour for the government to deliver something back that recognises the enormity of what nurses have faced.

In its submission to an ongoing pay review, Unison is demanding a £2,000 pay rise for nurses and their healthcare colleagues, while the Royal College of Nursing (RCN) union is demanding a 12.5 per cent increase.

“Everyone is doing their best to get through the pandemic and save lives,” Tuckwood said. But after a tough 2019-20 winter — when staff shortages were already acute with more than 43,000 vacant nursing positions across England — and surviving the first wave of coronavirus on adrenalin, the latest wave had been brutal, he said.

“Now it is chronic exhaustion. They [nurses] will keep on going as they can until things ease up a little. But a lot of people will be reassessing whether they want to continue in such demanding jobs.”

Wages and the impact of 10 years of budget cuts are one area of concern. But staff from several hospitals explained how Covid-19 had also challenged the fundamentals of their vocation, including their commitment to care for the overall welfare of patients.

In many critical care wards, there are too few staff on hand to turn intubated patients more than once a day. The normal ratio of highly skilled intensive care nurses to patients has fallen from one-to-one to one-to-four and occasionally one-to-six. Some hospitals are forced to rely on sedation to manage the critically ill.

“Sometimes you have nightmares. The day you are off you keep thinking of all the people that are passing away and worrying that you haven’t provided them with everything you should,” said one hospital nurse.

The nurse, who was not authorised to speak, said he felt completely burnt out and was only carrying on for fear of letting down his team.

“When your own mental health starts hurting, when you can’t smile like you should be smiling, you have to ask whether it is worth continuing,” he said.

Recent surveys point to how widespread these strains are. One in three healthcare workers are suffering from depression and a quarter from post-traumatic stress disorder, according to a study led by Birmingham university. These statistics, particularly for anxiety, were higher for nurses in patient-facing duties.

“Nurses I speak to every day tell me that they have no fuel left in the tank,” said Dame Donna Kinnair, general secretary of RCN, adding: “The government needs to fund support for burnt-out nursing staff, reward them properly for their work with a significant pay rise and draw up a fully funded workforce plan to boost the number of nursing staff.”

Andrea Righini, a senior nurse who worked for five years in Oxford and returned to Italy last month, said that every day felt like jumping into a sea full of sharks once he had witnessed first-hand how lethal the virus can be.

“You end up thinking why should I give my life to this virus when IT people get paid loads more to deal with viruses on computers?” he said.

The government has invested £15m to provide mental health support and advice for frontline NHS staff. The Department of Health and Social Care said that, while other public sector wages have been frozen, the government was sticking to a three-year pay deal for the NHS agreed with trade unions in 2018.

The government was also “on track to deliver 50,000 more nurses by the end of this parliament, in 2024 — with 11,088 more working in the NHS in the last year alone”, and an encouraging 23 per cent rise in UK nationals studying nursing.

There was an influx of professionals from India and the Philippines last year, according to the Nursing and Midwifery Council, the regulator. But the number of nurses on the register from the EU, the primary source of overseas recruits before the 2016 Brexit referendum, fell for the fourth year running.

Luigi d’Onofrio, another Italian nurse who returned home in January after six years in the UK, said the pandemic had taken a heavy toll. Brexit and dim prospects for better pay had contributed to his decision to leave. EU colleagues in his 1,400-strong Facebook group were tempted by jobs back home, he said.

What many in the NHS now dread, said a healthcare worker from London who asked not to be named, is the backlog of other issues that will loom as soon as the virus lets up. “When this is over we have that to look forward to,” she said. “But what we all need is rest.”