Concerns have been raised about a "backlog" of mental health patients in Scotland's secure hospital wards who are waiting to be moved to less restrictive care.

The Mental Welfare Commission raised the issue of human rights of patients in medium and low security forensic wards.

The commission said some are "being held in conditions of excessive security due to a lack of suitable places to move on to".

It comes as the commission published its first-ever Scotland-wide report into medium and low security hospital wards after visiting all 46 of them.

There were 400 patients being looked after in such settings and while many had either been sent there by the courts or transferred from prison, some had not committed any offence and were being treated in a secure setting because of difficulties providing care elsewhere.

The report also found that one in five said they felt unsafe, or partially unsafe, at times in the ward.

Six of the cases they examined involved "civil patients" who had spent more than 10 years in a secure environment.

Scotland has 14 medium-security and 32 low-security wards which have a combined total of 439 beds.

Alison Thomson, executive director of nursing at the Mental Welfare Commission, said: "Many of our findings are good, including positive comments from patients about the staff who care for them, and good access to advocacy and psychological services. This is welcome.

"But we were concerned about the human rights of patients who are being held in conditions of excessive security due to a lack of suitable places to move on to."

She continued: "We found that even after they have successfully won appeals at a Mental Health Tribunal, some medium secure patients were waiting to move on for longer than need be.

"In turn, low secure units were often finding it difficult to take these patients, as they themselves were having difficulty finding suitable places in the community for people ready to leave.

"This backlog in moving people to the least restrictive situation must be addressed."

The Commission's review did not cover the State Hospital at Carstairs as this is the subject of a separate report.

Maureen Watt, the Scottish Government's minister for mental health, said: "Protecting people's liberty and involving them in the decisions that affect them are at the heart of our mental health legislation.

"We made changes and improved legislation through the Mental Health (Scotland) Act 2015 to ensure that people with a mental disorder can access effective treatment quickly and it has given people more decision-making controls including independent advocacy, advance statements and named persons."

She said the Scottish Government would consider the commission's report.