Nurse staffing levels on many English hospital wards are dangerously unsafe, a group of senior nurses have said in an unprecedented warning.
The Safe Staffing Alliance (SSA) said one nurse should look after an absolute maximum of eight patients - but often nurses have to look after more, jeopardising patient care.
The alliance, which was formed last summer, and comprising senior expert nurses, said the 1:8 figure is based on hard evidence and it has issued new recommendations that "under no circumstances" should staffing be allowed to fall below that level.
A study by researchers at Southampton University found that hospitals with more than eight patients per registered nurse (during the day time on general acute wards) would see around 20 more deaths a year than better staffed hospitals. Those units with worse staffing levels could expect more "excess" deaths.
An SSA statement said: "For the sake of clarity, more than eight patients per registered nurse is the level considered to be unsafe and putting patients at risk. It is not a recommended minimum. For nurses to provide compassionate care which treats patients with dignity and respect, higher levels will be needed and these should be determined by every health care provider."
Katherine Murphy, chief executive of The Patients Association, pointed out that in the latest Care Quality Commission inpatient survey (CQC 2012) staffing levels were a key issue raised by patients.
She said: "Patients said they thought all staff, and in particular nurses, were overworked. A frequent comment was that staff were caring but that they 'did not have enough time for you'. The fact is without adequate staffing levels, overstretched nurses are not able to give patients the care they need."
Speaking on behalf of the alliance, Professor Elizabeth Robb, chief executive of the Florence Nightingale Foundation, added: "For the first time ever, nursing's leadership is united on this. We are coming together to stand up for patient safety and for the profession.
"We are saying that, with a ratio of one registered nurse to more than eight patients, there is a significantly increased risk of harm. We hope that by coming up with a figure we will give directors of nursing the evidence they need to argue for the staffing levels necessary to provide good care. If Government are saying that staffing levels are a local decision, then it is more important than ever to set out clear guidance."
The Government said hospitals were responsible for their own levels of staffing. Health Minister Dr Dan Poulter said: "It is for hospitals themselves to decide how many nurses they employ, and they are best placed to do this. Nursing leaders have been clear that hospitals should publish staffing details and the evidence to show that staff numbers are right for the care needs of the patients that they look after. Overall, the number of clinical staff in the NHS has risen and the number of admin staff has fallen by 18,000."