The government is not doing enough to address the problem of poor-quality food in the NHS and has repeatedly ignored warnings over standards, according an eminent figure in food studies.

Tim Lang, professor of food policy at London City University, has called for standards to improve hospital food to be legally binding, as the row over the quality of NHS meals continues.

Lang, who has advised the government on food and nutrition through Sustain, said more needed to be done to tackle the poor quality of NHS meals.

His comments come as the Good Food for Our Money campaign published a new report claimed that the failing system had cost UK taxpayers £54 million in the last decade.

It also claimed the government has ignored five warnings since 2006 that voluntary attempts to improve hospital food are failing.

Lang said: "Improving hospital food would bring great benefits to many millions of patients, but it would also inspire consumers to choose healthier food when out of hospital care and support British farmers to go even further to improve their produce.

"Having worked with government to improve hospital food for more than 10 years, I have come to the conclusion that to change hospital meals, the government must introduce clear food standards which are given strong legal backing."

Figures show that more than seven million people in the UK are vulnerable to malnourishment, including around 150,000 people in hospitals and 600,000 people in care homes, especially those with conditions like dementia or cancer.

The campaign’s co-ordinator, Alex Jackson, said: "Government has been deaf to repeated evidence that its 17 voluntary schemes over the past 10 years to improve hospital food have achieved next to nothing, at vast cost to taxpayers.

"Patients and their families want to see high-quality food that helps people recover from illness, and helps our farmers make a good living, while also protecting the environment."