Three-quarters of nurses do not think there are enough staff members to ''get the job done'', say Southampton researchers.

Only 24% of nurses believe that there are enough staff to properly care for patients.

And almost nine in 10 nurses said that at least one ''necessary activity'' was not done on their last shift due to lack of time - despite the average shift lasting for 12.8 hours.

Research, conducted by the National Nursing Research Unit, found that two fifths of nurses are dissatisfied with their job, with 44% saying they would leave their job if they could.

Researchers from King's College London and the University of Southampton said that there is an association between job satisfaction and patient to registered nurses ratios.

In wards where there were fewer patients to care for, nurses felt more satisfied with their jobs.

Nurses who had to care for fewer patients were also more likely to say that patient safety was good or excellent.

The study, conducted on almost 3,000 nurses who work in general medical and surgical wards 46 hospitals in 31 Trusts across England, found that overall, 31% of nurses said that patient care was ''acceptable'' with 7% saying it was poor or failing. Two thirds said patient safety was excellent or very good.

The authors of the study, who are working as part of the RN4CAST European research programme, also found that 42% of nurses are suffering from emotional exhaustion, with male nurses showing more signs of a ''burnout'' than their female counterparts.

More than a third of nurses said that important care information is often lost during shift changes and more than half think that ''things fall between the cracks when transferring patients from one unit to another''.

Jane Ball, deputy director of the National Nursing Research Unit at King's College London, said: ''The results provide clear evidence of the links between nurse staffing and the quality of care patients receive.

''On wards with poorer registered nurse staffing levels, nurses were more likely to say that care had been left undone due to lack of time.

''Working with inadequate staffing not only puts patients at risk, but places immense pressure on staff, and this has a knock effect on morale.

''Nearly half of the nurses we surveyed would leave their current job if they could. At a time when the number of nurses being trained is being cut, the service can ill-afford to lose this valuable expertise.''

Professor Peter Griffiths, chair of health services research at the University of Southampton, added: ''If there aren't enough staff, especially qualified nursing staff, then patient care suffers and certain tasks have to be abandoned due to lack of time and resources.

''This will obviously impact on staff satisfaction levels, with nurses feeling more stressed and less able to complete their job to the level they'd like.

''There were also other key issues which impact on nurses' job satisfaction, such as less than half feeling that they receive praise and recognition for good work and just over a quarter stating that they receive verbal abuse from patients or their families a few times a month.

''There is no denying that the NHS faces tough times ahead but this highlights both the importance and potential benefits of both managers and the public supporting nurses to ensure that they can deliver excellent care in the face of these challenges.''

The Royal College of Nursing (RCN) said there needs to be a system in place to guarantee safe staffing levels.

Janet Davies, executive director of nursing and service delivery at the RCN, said: ''The Government must sit up and take notice of these findings.

''Nurses regularly tell us that they are too busy to provide the standard of care they would like. When staff are pushed to breaking point, patient care is the inevitable casualty.

''Furthermore we know that over 60,000 posts are being lost in the NHS. In some areas, such as older people's wards, staffing levels are lamentably low and the workforce, despite trying their best, are stretched too thin.

''There needs to be a system in place to guarantee safe staffing levels.

''As well as harming patients and placing staff under huge pressure, this also affects NHS finances - the Boorman review identified over half a billion pounds that could be saved on a recurring basis if staff health and wellbeing was more effectively prioritised.

''Health Trusts and decision makers need to get a grip on this crisis in the making.''

Health Minister Anne Milton said: ''NHS providers should make sure they have enough staff at all times to ensure high quality of staff care.

''We recognise the link between good staff experience in the NHS and high quality patient care. This is an important study which will be useful to national nurse leaders as they develop their vision for nursing.

''We appreciate that nursing is a rewarding and demanding profession and local staffing levels need to reflect the care patients need.

''We take the health and well-being of our staff extremely seriously and we are aware that performance varies unacceptably from trust to trust.

''We are working with the NHS, NHS Employers and the Social Partnership Forum to focus on good practice, help the most challenged trusts and deliver high-impact changes to improve the health and well-being of all staff.''