AN IT expert and his wife who groomed and exploited a young girl to create a collection of pornographic photographs and videos are now behind bars.

Mark Williams, 44, and Elizabeth Williams, 43, of Moss Road, Latchford, were sentenced to eight years and six years respectively after pleading guilty to a series of child sexual offences charges.

The court heard how police uncovered the footage during an investigation into the distribution of child abuse images by Mr Williams.

On April 17, 2014, police carried out a search of the couple's home.

During the investigation electronic equipment was seized but many files on the devices were encrypted.

Despite repeated attempts by investigating officers to unlock the files, many remain concealed behind the encryption.

Some of the files were later accessed after Mr Williams revealed some of the codes to officers but he claimed he had forgotten the rest.

The footage uncovered showed Mrs Williams sexually assaulting the victim, who cannot be named for legal reasons, on three occasions.

The details of sexual assault are too graphic to publish.

Mr Williams, who made the recordings and photographs of the sexual assault, can also be viewed in another film dressing the young girl in a thong.

Prosecuting, Simon Parry said: "He was a man obsessed by sex and sexual depravity and he involved his wife as an active participant in the abuse.

"While Mark Williams was the instigator of the awful sexual environment, Elizabeth Williams took an active role to please her husband to fulfil his dark and depraved needs."

Other images recovered from the computer included pictures of the couple urinating in public and posing naked on the streets.

More than 27,000 images of child pornography were also found with some of the victims as young as 12 months.

This also included more than 9,000 images of bestiality.

Videos recorded by Mr Williams of young children and teenagers heading to school were also discovered.

Defending Mrs Williams, John Banasko said the defendant had felt sickened when she was shown the images and she had originally tried to defend her actions claiming she was in a hypnotic trance.

He said: "She fell under the spell of her husband as he was the one who downloaded the images, he was one who took the photographs and he was the one who had all of the photographs.

"She just went along with it."

Defending Mr Williams, Lloyd Morgan said the defendant is 'thoroughly ashamed and disgusted and full of self-loathing for his actions'.

But Judge Neil Flewitt QC said it was the clear the victim would be damaged by their actions.

He said: "I'm satisfied that Mark Williams was the instigator and the dominant personality and to some extent Elizabeth Williams was under his influence.

"But I'm extremely satisfied Elizabeth Williams knew entirely what she was doing."

Mrs Williams admitted three counts of sexual assault of a child.

Mr Williams admitted one count of sexual assault of a child, three counts of intentionally encouraging or assisting the commission of the offence by filming the sexual assault, two counts of taking indecent photographs of a child, five counts of making indecent photographs of a child, two counts of possession of indecent photograph of a child and one count of possessing extreme pornographic images.