There are too few nurses on wards to provide basic, safe care to older people, a union warned today.
It is calling on the Government to implement a patient guarantee, setting out the minimum number of nurses on older people's wards.
While its own research shows one nurse currently cares for about nine elderly patients, the RCN said one nurse to seven patients should be the maximum ratio for providing basic, safe care.
Ideally, there should be at least one registered nurse for between five and seven patients, it added.
A survey of almost 1,700 nurses, including 240 working on wards for older people, found 78% said comforting and talking to patients was not done or done inadequately on their last shift due to low staff numbers.
Some 59% said promoting mobility and self care was left undone or unfinished, while 34% said they could not patients with food and drink.
A third (33%) said they were unable to fully help patients to the toilet or manage incontinence.
In a new report today, the RCN also highlighted an "inappropriate" mix of registered nurses to lesser-trained healthcare assistants (HCAs).
The RCN has said the NHS is too reliant on untrained HCAs who are asked to pick up nursing skills as they go along. It has previously called for much tighter regulation and mandatory training.
However, the Government is not in favour of statutory regulation and has unveiled plans for a "code of conduct" and voluntary training for HCAs.
The RCN said today that hospitals are leaving too much in the hands of HCAs and recommends a ratio of 65% nurses to 35% HCAs.
Senior nurses should be able to decide their own levels locally depending on patient need, it added.
The RCN said the number of nurses on elderly wards compares poorly with other wards, such as adult general wards (6.7 patients per nurse) and children's wards (4.2 patients per nurse).
RCN chief executive, Dr Peter Carter, said: "Patients on older people's wards are being let down by systemic failings in our hospitals.
"Despite working tirelessly to provide patients with high quality care, nurses in these settings have repeatedly told us that they are unable to do this because of pressures caused by short staffing.
"It is unacceptable that there are not enough nurses on older people's wards.
"This is an outdated historic disadvantage dating back to 'geriatric' wards of the past and must be urgently addressed."
He added: "Safe staffing levels and mandatory patient to staff ratios are fundamental safeguards to provide quality patient care.
"The RCN has been monitoring and producing guidance on mandatory staffing levels for some considerable time, including working on a proposed amendment to the Health and Social Care Bill.
"Nurses also voted overwhelmingly for legally enforceable staffing levels at Congress last year.
"Now is the time for the Government to provide a guarantee that older people will get safe care."
Dean Royles, director of NHS Employers, said: "Mandatory staffing levels can not guarantee safe care.
"We do not believe that imposing a crude system of staffing ratios is the right way to tackle poor care.
"Each NHS hospital and service has different demands on its services. "Arbitrary ratios could limit organisations' ability to plan care in a way that is best for the patient."
In January, a survey of more than 2,500 NHS staff for Nursing Standard magazine found examples where HCAs were working beyond their competence.
Nurses cited cases where HCAs administered drugs without proper training, were left in sole charge of patients with complex needs and some were left running units and clinics.