A fifth of NHS hospitals are breaking the law on care of the elderly, according to a new report, with two trusts given prior warnings still leaving patients without intravenous fluids and one incontinent patient left unwashed despite asking for help.

The study, from the Care Quality Commission (CQC), found half of hospitals are failing to provide all-round good nutrition to elderly patients while 40% do not offer dignified care.

Of 100 hospitals investigated in England, 49 were found to have minor, moderate or major concerns about nutritional standards for elderly people.

In two hospitals, Alexandra Hospital (part of the Worcester Acute Hospitals NHS Trust) and Sandwell General Hospital (part of Sandwell and West Birmingham Hospitals NHS Trust), inspectors had major concerns about the way people were fed and given drinks.

Another 15 hospitals resulted in moderate concerns and a further 32 were listed with minor concerns. There were minor concerns about the dignity and respect provided to patients in 28 hospitals while a further 12 were told of moderate concerns in this area.

Overall, one in five hospitals was found to be breaking the law on one or both standards relating to dignity and nutrition. Just under half (45 hospitals out of 100) were fully legally compliant with the standards.

The CQC told how a follow-up unannounced inspection to Alexandra Hospital found its concerns have been addressed and the hospital is now meeting essential standards. However, when CQC inspectors returned to Sandwell General, they found that, although standards on nutrition had improved, people's dignity was not always respected.

The CQC found several "key themes" in hospitals that failed to meet the essential standard on dignity. These included call bells being put out of the reach of patients or not responded to quickly enough, staff speaking to people in a "condescending or dismissive way" and curtains not being closed around beds when personal care such as washing was done.

Those hospitals that failed on the essential standard for nutrition were frequently found not to be providing enough assistance with eating, while some patients had their meals interrupted and others were not taken to wash their hands before meals.

Dame Jo Williams, chair of the CQC, 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."