Police officers accused of being asleep when they were supposed to be protecting the royal family at Windsor Castle have been placed under investigation.

An unspecified number of officers from the Metropolitan police’s royalty and specialist protection team are being investigated after concerns were raised, the force confirmed. The Sun, which first reported the story, said up to 30 officers were involved.

The allegations include officers leaving posts unattended and sleeping while on duty.

The Met’s directorate of professional standards (DPS) had launched an investigation and the Independent Office for Police Conduct (IOPC) watchdog had been informed, the force said. The royal family has been informed.

A decision from the DPS over whether any of the officers under investigation should be placed on restrictive duties is expected before the end of next week.

The Met said the allegations of sleeping on the job and abandoning posts fell below its expected standards. A spokesperson said: “The Met’s directorate of professional standards has launched an urgent investigation following concerns raised regarding the conduct of a number of officers on protective duties at Windsor Castle.

“The allegations include officers leaving posts unattended and sleeping while on duty. The alleged behaviour falls below the high standards expected of officers, particularly in frontline protective roles.

“The Independent Office for Police Conduct has been informed and concluded that this matter will be investigated locally by the Met. As part of their inquiries, DPS is assessing whether any of those under investigation should be placed on restricted duties.

“A decision is expected to be made on this before the end of next week.”

Buckingham Palace declined to comment and the IOPC was unavailable to comment.