A police officer has been found guilty of battery after he struck a child who was in custody in the face.
Thames Valley Police sergeant Matthew Myers hit the 16-year-old boy and made him strip naked, the Independent Office for Police Conduct said.
The watchdog said he "abused his position as a custody sergeant" last year in Banbury, Oxfordshire.
The 49-year-old was sentenced to a community order and 200 hours unpaid work at Luton Magistrates' Court.
During the incident on 4 January 2020 the boy, who was in care and did not speak English as a first language, was left naked until a detention officer came into the cell to assist him.
The incident was referred two weeks later to IOPC investigators, who reviewed CCTV and spoke to detention officers and the child, before deciding to send the case to the Crown Prosecution Service.
Myers previously pleaded not guilty to the charge.
IOPC regional director Graham Beesley said: "Myers abused his position as a custody sergeant to assault a child and he has now been convicted of that offence.
"His primary duty is to ensure the safety and welfare of all those who are detained and assaulting a looked-after child who was vulnerable, where English was not his first language, is the exact opposite of what the officer should have been doing.
"The sentence shows that officers are not above the law and this kind of behaviour is not acceptable."
A Thames Valley Police spokesman said: "A determination will be made regarding misconduct proceedings.
"As such at this point, we would not be in a position to offer further comment."