A “depraved” serving police officer who downloaded more than 500 indecent images of children has been jailed.

One of the images downloaded by Mark Rosebury was a video lasting almost three hours which comprised 36 individual clips showing sexual abuse of children who were between two and three years old.

Rosebury, 38, who is an active police officer with Greater Manchester Police, also had images showing children as young as two and as old as nine being raped.

He denied having any sexual interest in children but Judge Robert Altham said that “simply cannot be the case.”

Rosebury, of Earnshaw Road, Bacup, appeared at Preston Crown Court on Wednesday, September 4 having pleaded guilty to three counts of making indecent images of children, one count of possessing extreme images, and one count of possessing a prohibited image of a child.

Niamh McGinty, prosecuting, said police attended Rosebury’s house on May 27, 2023, having received information concerning peer-to-peer file sharing.

Rosebury was suspected of using three IP addresses to access and download images – one linked to his home address and two connected to the East Lancashire Railway, where he was a volunteer.

His devices were seized and upon examination found to contain 257 category A images, 110 category B images, and 150 category C images, as well as three prohibited images of children and nine extreme pornographic images.

Further analysis found the first download of images took place in August 2022, while the last was in May 2023, two days prior to his arrest.

James Heyworth, mitigating, said Rosebury joined the police force in 2017 and had previously worked as a transport driver in the ambulance service.

In 2021 he was trained as a collision reconstruction expert, and he said in the pre-sentence report it was the numbness he experienced from this job that caused him to act in the way he did.

Mr Heyworth said: “Members of the public would expect police officers who serve them in the community would uphold the highest standards.

“He is essentially shocked by his own behaviour. Those around him, including his wife, are utterly shocked and surprised by what he did.”

Judge Altham, sentencing, said: “These images were accessed by you over a lengthy period of time. Let me make clear these are depraved, disgusting, and disturbing images, even of their time.

“One can scarcely imagine the anguish, distress, physical pain, and long-term damage caused to these toddlers being exploited in this way, and what you’ve done by downloading them is create a demand for them and validate the child abusers.

“Each of those children is a living, breathing human being who had been exploited in a horrible way so you could watch.

“Your work cannot provide any excuse or reason for you to resort to watching the suffering of children.

“When police officers commit offences there is a loss of public confidence in the police service as a whole.”

Rosebury was jailed for 18 months. He was also given a sexual harm prevention order for 10 years and must sign the sex offenders register for the next 10 years.