STRATHCLYDE Police are facing allegations that two officers assaulted a 14-year-old boy who had been involved in an earlier controversy, when he was held for more than two days in breach of the rules on the detention of young people.

The teenager has alleged that he was kicked several times, causing bruising to his ribs, and grabbed by the throat after the plainclothes officers forced him into an unmarked police car, two months after he had been held for 59 hours in two Glasgow police stations last year.

The allegations emerged last week, one month after the new Police Complaints Commissioner for Scotland (PCCS), Jim Martin, ordered the force to apologise to the boy and his mother when he upheld seven out of 16 complaints she made over his treatment.

The Sunday Herald understands the Crown Office was recently sent a report by the procurator fiscal in Glasgow, investigating the allegations made by the teenager, who is now 15. This paper has also seen documents which show Strathclyde Police's complaints and discipline branch is carrying out an internal inquiry.

The treatment of Child X, who two months before he was allegedly assaulted by the officers was arrested for being drunk and carrying a knife he had picked up in a Govan street, attracted widespread publicity. The episode provoked fears that police have detained other young people for long periods, against the terms of human rights law and police rules.

The boy was originally arrested at 2.30am on a Saturday in September 2006. He had sneaked out from his bedroom and had consumed alcohol given to him by a 17-year-old friend. His mother - a 48-year-old who holds down a respectable job, searched the streets with her husband before police contacted them at 5.30am. Police, who in this case were aware of the boy's identity and address, are required to make all possible attempts to contact the families of young people in custody.

When his parents arrived at Helen Street police station in Govan they found his trousers had been taken off and he was suffering from bruising, a cut to the head and other injuries. However, the police continued to hold him until Monday, when he attended a children's panel hearing.

Martin criticised the force for failing inform the family of his detention "within a reasonable time". He also referred the matter to Paddy Tomkins, chief inspector of constabulary for Scotland, who is conducting a UK-wide review into the detention of children in custody.

The latest incident took place on November 2 last year, when the teenager was charged with breach of the peace and resisting arrest in Govan. His mother insists it was his first time out of the family home after being grounded over the original incident. He was cleared of the charges after a trial at Glasgow Sheriff Court in May.

He allegedly told his mother that one of the officers grabbed him by the throat before handing him to a colleague, who kicked him "three or four times", according to his mother, as police tried to force him into an unmarked car. He ran away but was later re-arrested.

His mother said her son's injuries were recorded by a police photographer at Strathclyde Police's headquarters in Pitt Street, Glasgow. She added that the family's doctor also noted the injuries after carrying out an examination.

She said: "My son was held by the neck after he came out of the flats and given to the other officer, who kicked him three or four times in the back of the car. He was alleged to have sworn at the police when they approached him outside the flats because they weren't in uniform and he didn't realise who they were.

"The sheriff considered that no breach of the peace took place because they had not identified themselves as officers, so he had been illegally detained. He also said my son had every right to escape when he was being assaulted.

"The police tried to claim they had identified themselves, but the sheriff said he wasn't satified they had done so. He said it was for someone else to decide on whether the police had assaulted him, as it was not part of his remit. He said my son was a credible witness."

SHE claimed her son was targeted in an attempt to discredit him and damage the investigation into his detention. Commissioner Martin said in his report into the first incident that children should be detained only in cases of homicide or other "grave charges", or where it is necessary to keep a child away from a "reputed criminal or prostitute".

He added that various officers involved in the boy's detention failed to understand the force's procedures about the detention of young people. He described the incident as a "systemic failure".

His decision was welcomed by Kathleen Marshall, Scottish Commissioner for Children and Young People, who pointed out that the UN Convention on the Rights of the Child stated children should only be detained as a "last resort" and for the shortest "appropriate period of time".

A Crown Office spokeswoman said: "I can confirm we have received a report from the procurator fiscal in Glasgow and the matter is being investigated."

Strathclyde Police said: "This matter has been investigated. It would be inappropriate to comment further."