Polmont was inspected in March this year

HM Chief Inspectors of Prisons for Scotland, Andrew McLellan, made the recommendation as part of his assessment of Polmont near Falkirk.

He found that conditions in two of the halls were "very bad" and the system of slopping out was still in existence.

However, he praised Polmont for playing a part in maintaining family contact.

The report, which focused on the conditions in which prisoners live and on the way they are treated, was published on Wednesday.

It came as an announcement was made that slopping out had ended at Scotland's largest jail, Barlinnie in Glasgow.

The practice of some staff shouting and swearing at young adults and calling them by their last name should stop immediately Andrew McLellan prisons inspector

Mr McLellan, who carried out his inspection in March, found that problems were being caused by the fact the population of the institution had increased by 50% in the past year with about 650 inmates now being held including some under the age of 16.

The report stated: "There is not enough food for young men. The Visiting Committee, all prisoners, most members of staff, the catering department and the governor all identified this concern.

"During the inspection the food was generally good, but the portions were noticeably small."

Facilities in two of the halls, Argyll and Spey, were also criticised.

The report went on: "Conditions in two of the halls are very bad - 'slopping out' still exists in these halls in contrast to the excellent accommodation in Iona."

"Slopping out still occurs in Argyll and Spey, which means that under 21 prisoners on remand, who have not been convicted of an offence, have no access to toilets during the night (and often during the day when they can be locked up for considerable periods).

'Doesn't make it right'

"In many prisons, unconvicted prisoners have long and empty days with very little to do, and Polmont is no different."

Staff were also criticised for "shouting and swearing" at the young prisoners.

The report recommended: "The practice of some staff shouting and swearing at young adults and calling them by their last name should stop immediately."

Slopping out continues in some halls at Polmont

The report also criticised the fact that children under 16 have been locked up at Polmont.

It said: "Among those who spend a great deal of time alone in their cells are children under 16 detained in Polmont.

"It is not possible for Polmont to provide anything like suitable circumstances, conditions and activity for 14 and 15-year-olds.

"The report describes the conditions in which they are imprisoned. Children are only held in prison when no other place is available to them - but that does not make it right."