In her first report as chief inspector of prisons, Anne Owers has described Dartmoor prison as "the prison that time forgot".

Visitors to the prison discovered a wire mesh cage used to segregate suicidal prisoners from the others, while prison officers regularly described inmates as "rubbish" or "vermin".

This cage, the report says, was "more appropriate for dangerous animals than for potentially suicidal medium-to-low risk prisoners."

"When we reported our concerns about the cage, we were told that the governor had instructed that it be closed some weeks previously," it adds.

Of the inmates surveyed, six per cent complained of assaults by "someone other than a prisoner", interpreted to mean guards, compared to the national average of three per cent. Widespread racism was also reported.

Overall, the report makes 108 recommendations for improvement.

Speaking to the BBC Radio 4 Today Programme, the director general of prisons, Martin Narey, welcomed the "hard hitting but perceptive report". He added that he too had expressed concerns about the prison last year, and that a change in category for the prison should change conditions.

"There is a cage - the use of which I cannot tolerate - but it was only used for temporary periods when prisoners were being interviewed," he said.

"The change to category C status and the leadership of a new governor will change that once and for all."

Shadow home secretary Oliver Letwin also welcomed the report.

"We welcome this perceptive report, and we are glad to see that the Prison Service has embarked on bringing about much needed changes at Dartmoor," he said.

"Prisoners are human beings who deserve respect and must be treated properly. It is clear that Dartmoor has not caught up with improvements elsewhere in the Prison Service, and we look forward to seeing improvements carried out there in the coming weeks."

Liberal democrat home affairs spokesman Norman Baker said disciplinery action would be needed if action was not taken.

"This report would appear to be very timely. If we are to create a criminal justice system for the 21st century then our prisons must move with the times as well," he said.

"Urgent action is required to bring Dartmoor up to scratch, and if prison officers are unwilling to implement changes then the Prison Service should consider disciplinary proceedings."

The new governor, Graham Johnson, said he could not make any excuses for the report's findings.

"I will not defend inappropriate behaviour," he said.

Director of the Prison Reform Trust, Juliet Lyon, said the report was a welcome reminder that prisoners could be ill-treated in England, as well as abroad.

"At a time when the US government has been much criticised for violating human rights in its camp at Guantanamo Bay, the chief inspector's report on Dartmoor comes as a painful reminder that prisoners can be caged, degraded and abused in an English prison," she said.

"How was the prison allowed to sink over a long period of time to such an unacceptable level?"

Richard Garside, spokesman for crime reduction charity Nacro said: "Offenders are sent to prison as punishment, not for punishment. The conditions that the chief inspector found at Dartmoor prison are completely unacceptable on humanitarian grounds.

"They are also completely destructive of effective reform and rehabilitation work. Prisoners respond best when they are treated with dignity, humanity and respect."

However, Trevor Horn, director of the Prison Officers Association Devon branch, said he could not understand the report's criticism of Dartmoor's staff.

"We do not bully and we are not violent towards inmates," he said. "We had a brilliant report in 1997 and we have not changed in the way we do the job since then. We cannot recognise what they are talking about in this report."