Some youngsters have been kept in custody for several days, with one 15-year-old boy being detained for more than 88 hours.
The practice, which goes against a United Nations treaty protecting children’s human rights, has been described as “disturbing”, while Scotland’s Commissioner for Children and Young People warned police were in breach of the law.
The data, released under Freedom of Information legislation, also flags up significant disparities across the country.
Whereas officers in some areas, such as Grampian, say they did not detain a single child overnight during the period, the practice was routine elsewhere, despite a series of recommendations to overhaul and streamline the system outlined in an HM Inspectorate of Constabulary for Scotland inspection five years ago. No reasons were given as to why the detentions had taken place.
In the former Lothian and Borders force area, 187 children aged 15 or under were held in custody overnight, defined as a period which started before and ended after midnight. They included two 11-year-olds, ten 12-year-olds, and 21 13-year-olds.
Although most children spent only a few hours in custody, the records include a 14-year-old boy arrested and held for more than 36 hours, and another 14-year-old boy held for more than 26 hours.
One 15-year-old boy arrested in 2011 was held for more than 88 hours. The same year, two 15-year-old boys were arrested and held for more than 37 and 34 hours respectively.
In 2012, meanwhile, one 15-year-old boy was held for more than 59 hours after being arrested, while a 14-year-old boy was arrested and held for more than 21 hours.
In Tayside, the force detained 124 children aged 15 or under overnight during 2011 and 2012. They included eight 12-year-olds, six of whom were held for up to eight hours, and three 13-year-olds detained for up to 24 hours.
The former Northern Constabulary said it was not able to disclose the hours, but a nine-year-old, a ten-year-old, nine 11-year-olds, 37 12-year-olds, and 67 13-year-olds were among 664 detained children.
Not every force disclosed information. The former Fife, Dumfries & Galloway, and Central Scotland regions cited excessive costs, while the former Strathclyde Police said the information requested was not obtainable. This suggests the number of child detainees held in breach of the law may be significantly higher.
The length of time spent in custody by some of the children goes against Article 37 of the UN Convention on the Rights of the Child. It states that the arrest or detention of a child “shall be used only as a measure of last resort and for the shortest appropriate period of time”.
The Criminal Procedure (Scotland) Act 1995 says a child should not be kept in custody other than in exceptional circumstances, such as where they face a charge of homicide. Even then, they should be in a place of safety other than a police station.
Tam Baillie, Scotland’s Commissioner for Children and Young People, said: “It is clear that there are very significant variations in practice and this is a matter for concern. The fact that we are missing data from a very large section of the country may mean that the situation is worse even than this data indicates.
“It raises a question of consistency of practice, and if one area can produce a return of no children held in police custody it begs the question of why others produce such high returns. If some forces were not monitoring the use of police custody for children and as a result were unable to assess trends in their area, then presumably ministers did not have the oversight necessary to judge whether we were meeting our obligations in respect of domestic and international law.”
He added: “I have a concern that the number of children held is high compared to the number of children appearing in the Sheriff Court. We may be continuing to unnecessarily or inappropriately detain children in police custody. My hope is that a single police force will bring consistency.”
Alex-Cole Hamilton, head of policy at children’s charity Aberlour, said: “This data is deeply concerning. It’s something you might read about in more draconian societies, and it’s symptomatic of the fact we credit children with the mental capacity to decide between right and wrong at an incredibly early age, but don’t give them the rights that should go along with that.”
Chief Superintendent Ciorstan Shearer, of Police Scotland, said: “The safety and welfare of children is paramount when considering their detention in custody, and wherever possible a child will be released on an undertaking as quickly as possible.
“If this is not possible, police and social work staff working alongside parents and guardians will look for alternatives to detention in a police office. A decision to detain a child is made on a case-by-case basis.”
A Scottish Government spokeswoman said: “Children will only be kept in police custody as a last resort. Police have the powers, on the written authority of an inspector, to hold children in certain circumstances when it is in the interests of justice.”