For the vast majority of that time, he was a serving officer with South Wales Police.

His 210 victims were all aged between 10 and 16 years old - and Edwards has now been handed a life sentence, with a minimum term of 12 years.

The team who led the investigation into his crimes say there are many more victims they are yet to identify.

Detective Superintendent Tracy Rankine told Sky News that Edwards "didn't assist at all with this investigation".

She said: "The way that he had his devices and his computer networked, if you were to just simply unplug it and take it away, it had a degree of encryption on it, so it would have wiped it.

"We had to make sure that when we recovered the evidence, we did so at the scene and the experts built the appropriate software to enable us to download the material then and there so we didn't risk losing anything."

Ms Rankine said Edwards had a "directory of folders that had numbers next to it".

"We were very easily able to see that the number related to an age profile and the images within that folder, so the way that things were recorded was really quite organised," she added.

Lucy Dowdall, a specialist prosecutor with the Crown Prosecution Service's organised child sexual abuse unit, told Sky News that Edwards is "an extremely manipulative person".

"He relied heavily on the embarrassment and fear of his vulnerable victims to ensure that they would not report to anybody as to what had happened," she said.

"As a police officer, there would be a position of trust as with anybody who holds such a position of responsibility.

"But anybody who deliberately targets vulnerable children is abusing some level of position and it's important that they're all brought to justice."

'I have my GCSE tomorrow'

During the three-day sentencing hearing, Cardiff Crown Court heard powerful testimony from some of Edwards's victims.

Such was the nature of the case that the prosecution was, at one stage, close to tears.

Edwards's youngest victim was 10 years old.

One girl begged Edwards to stop demanding indecent images and videos of her.

"Please can you stop, I have my GCSE tomorrow morning, please, I'm begging you," she told him.

In a victim impact statement read out on their behalf, the girl's parents said their daughter now experiences "full-blown panic attacks that can be triggered by quite small things".

The court heard how another of the victims told her father about what Edwards had been asking of her.

He took his daughter's phone and sent Edwards a message saying, "This is [the girl's] dad. Stop now. What you are doing is illegal."

Edwards replied: "Lol."

Her mother said there were "many occasions when I know she contemplated suicide".

"She was too scared to miss a message in fear of what he would do," she said.

The mum said she could "only conclude that Lewis Edwards is a very broken human being".

Only one of Edwards's victims dates back to before his period as an officer at South Wales Police.

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