A police watchdog has launched an investigation after an officer allegedly broke a 15-year-old boy’s arm while detaining him outside a Shefford supermarket.

The alleged incident is described by the Independent Office for Police Conduct as happening outside the Morrisons supermarket off St Francis Way, at 6pm on December 14 last year.

During a police operation involving a number of officers and teenagers, it is alleged an officer took the 15-year-old to ground – with the boy suffering a head injury and broken upper arm.

The teenager was later taken home, and no further police action was taken against him.

The Bedfordshire Police professional standards department referred the incident to the IOPC last month.

The IOPC says it will now be investigating “the level of force used by the police officer as well as the actions of other officers at the scene and at the teenager’s home, and the care provided to the teenager following the injury”.

IOPC regional director Sarah Green said: “A teenage boy has sustained a serious injury while being detained by police and it is vital we establish what happened and how officers reacted afterwards.

“This would have been a busy time at the supermarket in the run up to Christmas, and I would urge anyone who may have seen this incident to contact the IOPC as soon as possible to assist in our investigation.”

Anyone with information should email the IOPC on sheffordincident@policeconduct.gov.uk or call 0800 096 9078.