Elderly people suffering from conditions such as Alzheimer’s disease are being denied food and drink, while just one in five hospitals makes sure that nurses are told if their patients have such a diagnosis.

The audit, involving almost 8,000 patients with dementia, found that less than half were given basic tests to assess their brain function – and diagnose their condition, or its deterioration – when they were admitted.

Just 19 per cent of hospitals made sure staff on the wards were told if their patients were suffering from conditions like Alzheimer’s disease and less than 5 per cent of hospitals insisted that clinical staff underwent compulsory training in dementia awareness.

Although malnutrition is known to be a factor which can cause those with dementia to deteriorate, 30 per cent of patients were given no nutritional assessment – and by the time they left hospital, more than 42 per cent had lost weight, the audit by the Royal College of Psychiatrists found.

Separate statistics have shown that in 2009, more than 13,500 elderly people became malnourished while they were in hospital.

Charities say frail dementia sufferers who are too weak and confused to feed themselves are left to starve, with meal trays placed beyond reach of bedridden patients and then taken away, completely untouched.

Campaigners fear nurses are too busy to carry out basic duties of care, such as helping the most vulnerable to eat and drink.

Professor Alistair Burns, the Government’s dementia tsar, has written to NHS senior managers across the country urging them to act on the “disappointing” findings from the national independent audit.

The report says ward staff who do not realise that patients admitted for other reasons suffer from dementia can neglect their needs, leaving such patients at risk and with their dignity compromised.

Symptoms of dementia can include aggression and agitation, and when staff are unaware that a patient is suffering from the condition then they are more likely to give an “inappropriate” response to such behaviour, the report points out.

Nurses are advised not to move patients suffering dementia too often, and in particular, to try not to move such patients at night, when they are more likely to feel panicked by changes. yet the audit found that less than one in three hospitals maintained that standard.

After being admitted to a ward, 40 per cent of dementia patients were moved around the hospital, with some being transferred from one bed to another more than five times.

Patients are moved within hospitals in order to make space for new patients on particular wards, and after operations, or because of outbreaks of infections.

The report found that 12 per cent of patients with dementia were moved between two and six times during their hospital stay.

About 750,000 people suffer from dementia, and more than half of those suffer from Alzheimer’s disease. The figures are expected to double in 40 years, as the population ages.

Andrew Chidgey, head of policy at charity the Alzheimer’s Society, said the findings from the national audit had left experts feeling concerned.

He said: “We knew the situation was quite bad in some hospitals, but I think a lot of us are pretty shocked to see a national picture like this – a lot of these failings are very basic.”

Mr Chidgey said that too often, elderly people with dementia, who were admitted to hospital for other reasons, such as for a hip operation, deteriorated while they were on the ward, and were in worse physical and mental health by the time they left.

He said: “Often because staff are not aware of the dementia, the patient doesn’t get the appropriate care and becomes increasingly confused and agitated.

“They don’t get the help they need eating and drinking, they get given inappropriate medication, and by the time they leave they are malnourished, and the symptoms of their condition have worsened.”

He said giving patients with dementia the right care would save the NHS money, while failing to look after them properly meant they spent far longer in hospital than they needed to.

Katherine Murphy, from The Patients Association, said the most vulnerable patients and their families were left feeling “desperate” because of repeated and unjustifiable failings across the country.

She said: “What does it say about our society if we can’t assist elderly people who need help eating?

“These people are vulnerable and require the utmost care and attention. They deserve their humanity, they deserve to be treated with dignity,” she added.

Mrs Murphy said she was appalled at the number of times such patients were “shunted around the hospital” given that many would already feel bewildered and unsure of their surroundings”.

The charity is calling on the Government to bring in an independent matron for every hospital ward, to improve standards of care.

Paul Burstow, the care minister, said: “There can be no excuses for these shocking findings. The audit is a snapshot of the state of dementia care in our hospitals twelve months ago.

“It shines a spotlight on poor practice that demands action from the NHS.”

He said the Government had already set out ways in which hospitals must take urgent action to improve the care of people with dementia.