NHS staff are quitting to stack shelves in supermarkets instead of caring for patients because they are so demoralised by years of getting pay rises of only 1% or nothing, hospital bosses have warned.



The health service is now so understaffed that patient safety is being put at risk and people with mental health problems are experiencing delays and setbacks as a result, NHS leaders say.



The intervention in the general election campaign comes from NHS Providers, which represents almost all of England’s 240 NHS hospital, mental health and ambulance trusts. They told ministers bluntly on Monday that the government’s longstanding policy of holding down NHS staff pay is wrong and is damaging the service by deepening its already severe staff shortages.



“Years of pay restraint and stressful working conditions are taking their toll,” said Chris Hopson, NHS Providers’ chief executive. “Pay is becoming uncompetitive. Significant numbers of trusts say lower paid staff are leaving to stack shelves in supermarkets rather than carry on with the NHS.”

He urged Theresa May to abandon her plan to limit NHS staff’s pay increases to 1% a year until 2020 and not pursue it during the next parliament as a way of making the NHS’s books balance.



He added: “Trust leaders tell us that seven years of NHS pay restraint is now preventing them from recruiting and retaining the staff they need to provide safe, high-quality patient care. The NHS can’t carry on failing to reflect the contribution of our staff through fair and competitive pay for five more years.



“Pay restraint must end and politicians must therefore be clear about when during the lifetime of the next parliament it will happen and how.” He repeated the organisation’s demand for £25bn in extra funding to help the NHS in England get through until 2020 and warned that staff are also leaving because they are exhausted from having to work so constantly to keep up with the unprecedented demand for care.

Hopson added: “We are getting consistent reports of retention problems because of working pressures in the health service causing stress and burnout.”

Medical royal colleges, health trade unions and health charities such as Cancer Research UK have been highlighting in recent months the damaging effects on patient care of widespread shortages of doctors, nurses, GPs, paramedics and many other NHS staff groups.



Norman Lamb, a former coalition government health minister, said NHS pay restraint – which had operated since 2010 – was “stupid” and had gone on so long that it was proving counterproductive.



“The Conservatives expect NHS staff to take year-on-year real-terms pay cuts in order to try to stave off financial disaster in the NHS,” said the Liberal Democrat health spokesman. “You can’t possibly justify this over such a long period. It is also stupid because great staff will vote with their feet and leave.”



He contrasted his party’s plan for a 1p increase in income tax to generate extra funds for health and social care with May’s refusal to commit to any tax increases for that purpose. With the Tory majority set to increase, “this guarantees a bleak future for the NHS and for its staff under the Conservatives”, claimed Lamb.



Jeremy Hunt, the health secretary, repeated his pledge of more money for the NHS if the Tories are re-elected and said that nurses’ pay should go up. Responding to a question from the BBC interviewer Andrew Marr about some nurses going to food banks, Hunt replied that average nurse’s pay is £31,000.



“Is that enough considering the brilliant work that they do? I think many people would say they want to pay them more. I think they do an incredible job. If you want more money to go into the NHS – and this government recognises we will need to put more money into the NHS and the social care system because of the pressures we face – then the question is how you get there,” said Hunt.

He also insisted that key NHS waiting time standards, such as the four-hour target in A&E and 18-week wait for planned hospital care, were not particularly useful measures of true NHS performance. Lives saved from cancer and heart disease as a result of better care showed the service was doing well, he added.

Jonathan Ashworth, Labour’s health spokesman, said Hunt’s agreement that it was unacceptable that the A&E target had not been met in England for more than two years was “an admission of failure straight from the horse’s mouth: the Tory-made A&E crisis is simply ‘not acceptable’”.

Responding to Hopson’s comments on NHS pay, Ashworth added: “This is a stark warning from NHS Providers about the Conservatives’ catastrophic management of the NHS workforce. It is incredible and disgraceful that NHS staff are leaving to work in supermarkets instead because NHS pay has been squeezed so far. The country’s shortage of paramedics, nurses and consultants now threatens a raft of NHS strategies to provide better services for patients.”

NHS Providers are also warning that understaffing is so serious in mental health services that patients are now suffering delays in receiving treatment, taking longer to recover and having a bad experience of NHS care. “We are particularly worried about the pressures in the mental health workforce,” said Hopson. “These are resulting in delays in treatment, people are taking longer to recover, and as a result their care is more expensive and their experience is worse.”

A Conservative spokesman declined to respond directly to Hopson’s warning. He said only that: “As NHS England say, outcomes for every major disease in this country are now better than they’ve ever been. But the truth is that in order to continue to invest in the NHS, grow staff numbers and pay, and improve patient care, we need to secure the economic progress we’ve made and get a good Brexit deal. That is only on offer at this election with the strong and stable leadership of Theresa May.”