A former constable with Greater Manchester Police “undermined public confidence” in the force after he collected a vast number of online images of female colleagues and police cadets as young as 12 and then shared them on paedophile websites.

Christopher Dunn, 33, of Swinton, Greater Manchester, manipulated some of the collected images – including children of officers – to make them sexually graphic and encouraged other paedophiles to show their appreciation of the pictures.

More than 100,000 indecent images of children were found on his desktop computer, together with evidence of more than 100 highly organised folders including “sorting school girls”, “cadets”, “cops” and the individual names of particular victims whose photographs he had harvested from social networking sites without their knowledge.

Manchester Crown Court heard the computing graduate began collecting the images the same month he joined Greater Manchester Police (GMP) full time in January 2014 after previously serving as a special constable in the force.

Such was the complete absence of suspicion, he received a divisional commander’s commendation for good service in October 2016 and a divisional commander’s “good work minute” for dedication to his role as police cadet leader in August 2017.

In September 2017, he was allocated as a “subject matter expert” to a team tasked with setting up the new GMP force-wide computer system.

His double life came to an end when officers attended his home in February and arrested him after an investigation was launched when he uploaded an indecent image to a messenger service in October 2018.

Following his arrest, Dunn said: “I’m not like one of those paedophiles who touch children. They make me sick.

“My life is effectively over. I want to talk to show that I am not one of them.”

Dunn pleaded guilty at an earlier hearing to three counts of making indecent images of children, three counts of possessing indecent images of children, two counts of distributing indecent images of children and two counts of misconduct in a public office.

The Independent Office of Police Conduct (IOPC) said the offences related to 57 victims.

On Wednesday, Mr Justice Bryan sentenced him to four years and four months in jail.

He told Dunn: “You were in a position of trust and responsibility in relation to young, and often vulnerable, police cadets.

“You betrayed that trust in harvesting pictures of them for your own personal gratification, and posting them on paedophile websites for the sexual gratification of others who shared your unhealthy interest in young females.

“Those young cadets will have to live with what you have done for the rest of their lives.

“You were placed in a position of trust and responsibility to work with police cadets.

“You have violated that trust and your actions have undermined the fabric of the police service and undermined public confidence in Greater Manchester Police.

“At the same time you have caused considerable harm and distress to your fellow police officers and their families.

“It is almost beyond belief that someone could have distributed pseudo-images of their colleagues and their children on pornographic websites but that is exactly what you have done.

“It is quite clear that your motive was sexual, and whatever your denials that you have an unhealthy interest in young females.”

Dunn was dismissed from GMP in May and will be placed on the College of Policing barred list which prevents him from working in any law enforcement agency in the future.

He has also been placed on the sex offenders register and will be subject to a sexual harm prevention order for life.

Following sentencing, Detective Chief Inspector Richard Eales, of GMP, said: “This case is extremely shocking for everyone – the victims in the case, the public, his colleagues and those who investigated his crimes.

“At the start of our policing careers, we take an oath to protect those who are the most vulnerable and uphold fundamental human rights, something which he has outrageously breached.

“This has been a thorough investigation and those who have been affected have been at the very forefront of all of our inquiries to make sure we get justice for them.

“He is not representative of GMP, nor of the policing service as a whole, and I cannot praise the actions of those who have come forward enough and helped us with our investigation despite the pain and hurt this case has caused them and their families.”