Jeremy Laxton and Jack Addis, who are both 63 and left the Met more than a decade ago, served with Richard Watkinson, 49, in the force while based in Ealing, west London, from the late 1990s up until 2002.

Southwark Crown Court heard that while on duty as a chief inspector Watkinson shared information and an image of a 14-year-old boy, who was the subject of a missing person investigation with Laxton for their "sexual gratification".

Laxton was jailed for five years and nine months and Addis was sentenced to three years and nine months on Friday after earlier admitting to conspiring with Watkinson to distribute or show indecent images of children.

More than 5,000 pictures and videos were shared on a Toshiba hard drive found in Watkinson's mother's house.

The court heard how the men would meet - including for an Indian meal - to transfer indecent images of children to the device, which served as a library they could all use.

Prosecutor James Dawes KC said some of the material included babies and children under the age of five.

Investigators discovered other devices, including laptops and mobile phones, in a specially constructed hide built into the wall cavity under the stairs of a property Laxton owned in Lincolnshire.

Mr Dawes said a video found was described by a police officer as "one of the most disturbing" child abuse images in existence.

Laxton also pleaded guilty to three counts of making indecent images of a child, possession of a prohibited image of a child, possessing extreme pornographic images, possession of cannabis, and intentionally encouraging or assisting the commission of the offence of misconduct in a public office.

He joined the Met in 1980 and retired at constable rank in 2010, while Addis, who joined in 1978, attained the rank of sergeant and served as a firearms officer for 15 years before joining the Civil Nuclear Constabulary in 2010.

Watkinson, who served as chief inspector for neighbourhoods policing at the West Area Command unit, was found dead at his home in Saunderton, Buckinghamshire, on 12 January - the same day he was due to answer bail to be charged - and the court heard he took his own life.

He had been suspended since his arrest in July 2021 and faced conspiracy charges, as well as prosecution over allegations of voyeurism, misconduct in public office and three counts of making indecent photos of a child.

Addis, from Dumfries, is already serving an 18-month sentence for voyeurism and possession of indecent images in Scotland, while Laxton previously admitted other indecent images offences at Lincoln magistrates' court.