As 20 per cent of NHS trusts struggle to cope financially, a similar proportion have been condemned in a separate report for failing to meet minimum legal standards in the provision of food and the maintenance of dignity for their patients.

In one trust, inspectors found doctors had resorted to writing prescriptions for drinking water to ensure patients had enough. The report, conducted by the Care Quality Commission (CQC), added that half of the 100 trusts surveyed were failing to do enough to meet patients' needs and must improve.

The findings were drawn from 100 unannounced inspections of NHS acute hospitals which took place between March and June.

A warning notice has been issued to one hospital, the James Paget Foundation Trust in Great Yarmouth. Inspectors re-visited it in September after moderate concerns were raised in the summer, and found patients in need of intravenous fluids did not have infusions. The trust could be prosecuted if it does not make swift improvements.

Dame Jo Williams, chairwoman of the CQC, said: "Too often, our inspectors saw the delivery of care treated as a task that needed to be completed. Those responsible for the training and development of staff, particularly in nursing, need to look long and hard at why the focus has become the unit of work, rather than the person who needs to be looked after."

She said staff must not prioritise processes over people, adding: "Task-focused care is not person-centred care. Often, what is needed is kindness and compassion, which cost nothing."

Michelle Mitchell, of Age UK, said: "These findings show shocking complacency on the part of those hospitals towards an essential part of good healthcare and there are no excuses. Not ensuring that a patient eats well enough to aid their recovery is a basic failing. The Government must compel all hospitals to publish data showing malnutrition rates on their wards in a form the public can understand."

The Health Secretary Andrew Lansley said the failings were "unacceptable" and said local HealthWatch organisations should carry out unannounced independent inspections. "Working with CQC, HealthWatch will be champions for patients' quality of care," he said.