Inspectors found 122 youngsters had been held at the Dungavel House unit in Lanarkshire in the first 11 months of last year, up from 94 in the whole of 2005.
They also discovered children were, on average, spending longer in the facility, with at least two detained for more than a month.
Their findings, however, represent a huge improvement from conditions three years ago, when the Ay family, in a notorious case, spent more than a year in Dungavel.
Her Majesty's Chief Inspector of Prisons, Ann Owers, in a report released last night, said the facility, an "immigration removal centre", was now the best of its kind in Britain.
"Dungavel is the best-run IRC we have inspected," she said. "We found examples of good and innovative practice, which could and should have been copied elsewhere".Ms Owers praised the unit, which is run by the Border and Immigration Agency, for a range of advances, including in welfare, religious affairs and education.
Ken Paul, Dungavel's director, said: "These comments reiterate our commitment to providing a service to those in our care based on the fundamentals of dignity, welfare and respect."
The report, however, did little to reassure campaigners who have been raising concerns about Dungavel since it opened in 2001.
Jock Morris, chairman of Glasgow Campaign to Welcome Refugees, said: "It would be hard for Dungavel to come out worse than some of the other detention centres, considering how bad some are.
"But the fact the place is reasonably run, although welcome, is not the issue. The problem is that children who have committed no offence are still being locked up."
Ms Owers raised some concerns about the number of children at Dungavel and the amount of time they were spending there.
Seven youngsters were held for more than seven days, including two for 32 days, in the 11-month period covered by the inspection. That took the average stay for children up from three days in 2005 to three and a half days in 2006.
"The detention of children should be exceptional and for the shortest possible period, and the interests of the child should be fully considered before detention is authorised," the report recommended.
Adults were sometimes handcuffed when they left the centre to accompany their children to hospital appointments, found the report.
"Detainees under escort should be handcuffed only following individual risk assessment," the inspectors recommended. "A previous recommendation this practice should be stopped had been accepted but it nevertheless continued," noted the report.
The report was pleased to note just 3% of detainees reported being subjected to verbal or physical racial abuse, compared with up to 12% at other IRCs. Use of force was deemed to be "minimal and appropriate" - 33 incidents had been recorded in the first 11 months of 2006.
Source: The Herald