A man who has served jail time for having a million indecent images of children is back behind bars after being caught distributing similar vile material.

Christopher Roche got six years in 2011 for having and distributing the vast horde of pictures and movies as well as for abusing a child in the 1970s and 80s.

But after his release from prison the 53-year-old former NHS fraud investigator returned to his old ways.

Colin Meeke, prosecuting, told Swindon Crown Court that intelligence revealed that the defendant had been sharing images on a peer to peer network.

Police raided his home and seized his phone and computer media which were found to contain the images.

He said there were 176 pictures and 29 movies in the worst category, 181 images and 62 films in the middle band and 756 pictures and 13 movies in the least serious.

"In addition to the number of images that had been counted, there were many thousands more images which the police simply don't have the resources to examine in detail: many are indecent images of children. There are several tens of thousands of those," he said.

Mr Meeke said that while the software on the computer allowed the material to be shared with other users it was not clear who had accessed what.

"It is not easy to say what images were shared over a period but it is clear a large number were available and had been shared," he said.

When he was questioned the defendant admitted what he had done and accepted he was sexually attracted to children.

Roche, of Belle Vue Road, pleaded guilty to three counts of making and one of distributing indecent images of children.

Richard Williams, defending, said that when he was questioned he said he was glad to be caught as it stopped him offending.

He said he was ashamed of what he had done and acknowledges that he has a problem which needs to be addressed.

Jailing him Judge Tim Mousley QC said: "You are someone who has deeply entrenched characteristics in this way and you have had them for many years.

"And it seems you will retain them for many years unless of course the help you can get has any success. I also accept at the moment you lack the motivation to stop offending.

"There is also the risk that you commit contact offences as you have in the past, albeit many, many years ago."

He jailed him for four years with a four-year extended licence meaning he will have to serve two thirds of the custodial element before he can apply for parole.

The judge also imposed a new sexual harm prevention order restricting his liberty and he must register as a sex offender for life and is barred from working with children.

An NSPCC spokesperson for South West England said: “Roche’s crimes are far from victimless – children suffer the most horrific abuse for the images he downloaded to be made. Collecting and sharing these images, as Roche did, fuels the demand for more children to suffer.

“He must be policed effectively on his release from prison to aid his rehabilitation and to prevent any further repeats of his offending.”

Any adult concerned about the welfare of a child or young person can call the NSPCC helpline for free 24/7 on 0808 800 5000.

Meanwhile, children can call Childline on 0800 1111.