Almost two-thirds of nurses believe there are too few of them working in the NHS to keep patients safe and give them proper care, a survey has revealed.

Understaffing and the increasingly complex medical needs posed by an ageing population are creating a “deadly mix” for patients, the Royal College of Nursing warned on Monday.

More than one in five (22%) of nurses working in hospitals or community settings across the UK told the RCN that the number of nurses on duty in their last shift was “well below what was needed”, which left care “significantly compromised” and a “high level of risk of harm to patents and staff”.

Of the more than 13,000 nurses who took part in the survey 64% said they thought that the number of registered nurses on that shift was “below” or “well below” what was needed to ensure safe care.

One nurse working in an A&E in England told the union: “The shift was completely unsafe and it felt like a miracle that avoidable harm was not caused.”

Prof Nicola Ranger, the RCN’s chief executive and general secretary, will urge ministers to bring in mandatory minimum safe nurse staffing levels when she opens its annual congress on Monday.

“Widespread vacancies of registered nurses are always unsafe,” she said. “But the risk is being compounded by the demands of delivering ever more complex care to an ageing, sicker population, with multiple conditions. It’s a deadly mix.”

Speaking in Liverpool, she will accuse ministers of failing to ensure that the health service has enough nurses and the nursing profession is being “set up to fail”.

Frail, elderly patients are at particular risk from the lack of nurses, the RCN warned. A nurse working on an older people’s ward in England said: “Managing high-risk fall patients who require one-to-one supervision is simply not achievable with current staffing levels.”

The growth in the nursing workforce slowed last year to its lowest level in eight years, figures released by the RCN show. Over the past decade the rate of increase in the number of doctors employed by the NHS in England has outstripped that of the nursing workforce by 51%, it added.

A Department of Health and Social Care spokesperson said: “Nurses are the backbone of our NHS, and support patients both physically and emotionally in their most vulnerable moments. It is vital that they are equipped with the tools and resources they need to deliver world class care to those who need it.

“We have recruited 16,000 more nurses and health visitors since we were elected in July 2024, and our upcoming 10-year workforce plan will set out a clear roadmap to improve working lives in the NHS, including better treatment of staff, higher-quality training, and more fulfilling roles.”

Meanwhile, NHS bosses in England have warned that hospitals will have to make “deep cuts” to services this year because they do not have enough money.

A survey of the leaders of health trusts by the membership body NHS Alliance found that:

• 64% expected to cut services this year.

• 83% feared financial constraints will impact planned patient care and 78% worry it will affect emergency care.

• 57% expected to cut their clinical staffing this year to save money.

Ciaran Devane, the organisation’s chief executive, said that “in many ways the NHS is starting to turn a corner”, with shorter waiting times and higher public satisfaction. But progress is at risk, with “likely service closures and job cuts this year”, because the service needs more money to do its job properly.

A DHSC spokesperson said: “We recognise the challenges NHS leaders face, but this government has supported the health service with record investment, boosted productivity, and driven improvements in tech.

“Waiting lists are at their lowest level in more than three years, and over half a million fewer people are waiting for treatment since July 2024. We’ve also expanded community diagnostics, surgical hubs and GP appointments to get patients seen faster.”