It does not make for pleasant reading and it is unlikely to get your appetite going either:

mashed potato made from frozen pellets, bechamel sauce made from ready-made mixtures and frozen, and food left in the oven for so long that it is completely dried out.

On a television cooking competition, it would be funny. It is not so funny when it is happening in Scotland's hospitals.

The scale of the problem in hospitals has been clear for many years, but the unpleasant new details have been uncovered by the restaurateur David Macguire, who was allowed to observe the way meals are prepared for patients by NHS Greater Glasgow and Clyde.

As well as the potato pellets and powdered bechamel, Mr Macguire also discovered bizarre practices such as painting brown spots on mash to make it appear caramelised. It amounted, said the restaurateur, not to food that people would love to eat, but what he called a pastiche of food.

"It reminded me of the worst components that I have encountered at school meals," he said. "I am astonished that anyone eats any of it."

Mr Macguire says he first became worried about NHS Greater Glasgow and Clyde's food when his sister was in hospital after a motorbike crash, and he believes some of the problems could be fixed with a few simple steps, such as changing the working hours of kitchens or improving the trays in which food is kept.

However, the suspicion is that the problem with hospital food is much more fundamental and reflects a culture in which cost has been prioritised over quality. NHS Greater Glasgow and Clyde undertook a major re-organisation of the way patient meals were prepared during 2011 and 2012 which meant all meals are now handled by two central kitchens where the food is cooked and frozen before being transported all over the region.

By the time it is wheeled out in front of patients, it is often dried out or watery. It is rarely appetising.

NHS GGC says it has recruited an expert in mass catering to help drive up quality, but part of the problem is that the catering budget was cut by almost £1million in 2012 and the board now spends barely £4 per day per patient in some of its hospitals. Try to imagine what kind of food and drink that would buy you outside the hospital and you will form a pretty reliable idea of why the standard of food in hospitals is inadequate.

No health board has an easy job in trying to feed thousands of patients every day across large areas (NHS GGC alone is preparing more than a million meals a month) but cutting back on the quality of food is a false economy. A healthy, varied, fresh diet is a vital part of good care and can help patients recover more quickly and return home.

Sadly, Mr Macguire's investigation is further evidence that NHS GGC is not doing well enough. NHS resources are tight and reheating pre-packed food is cheaper and easier than making meals from scratch on site. But patients should be able to expect nutritious, healthy, fresh food every day. However it is delivered, that should be the minimum standard.