A prosecutor has described a video used by vile child sex abuser Matthew David Graham, showing an assault on an 18-month-old girl, as 'one of worst things you could see'.

The case, presented by prosecutor Krista Brekweg, was named as one of the most distressing ever to come before the court.

The video description was contained in a statement made after Graham pleaded guilty to 13 child pornography and sex offences on Wednesday in the Victorian County Court, The Herald Sun reports.

Scroll down for video

Matthew David Graham, 22, was described as so depraved that even other paedophiles did not like him ‘because of his cruelty’

Judge Michael Tinney only reluctantly agreed to view edited images and video. One video as evidence was titled 'Daisy's Destruction'.

Graham was allegedly so cruel even other paedophiles could not stand him, the court reportedly heard.

Graham pleaded guilty in September to setting up child pornography websites on the 'dark web'.

When Graham was 18, he was on the cusp of graduating from Epping Secondary College, in Melbourne's north, and lived a quiet life with his parents in the neighbouring suburb of South Morang.

But behind closed doors he was leading a very different life. Under the name 'Lux', he controlled a network of concealed 'dark web' websites and forums used by paedophiles,The Age reported.

In particular, Graham's services offered an extreme form of a child pornography called 'hurtcore', which shows sickening torture and sexual acts being carried out on children, even babies and toddlers.

Two of his websites were called 'Hurt 2 The Core' or 'Love 2 The Core', and as a condition of membership people were required to upload a certain number of videos.

On these sites, users had access to child prostitutes, images under titles including 'delicious little boys' and 'yummy little girls', and videos of 'sexy little' boys and girls, The Kernel reported.

A sample of topics on Hurt 2 The Core's message boards in June 2013 included 'Producing kiddie porn for dummies', 'Toddler childporn star', 'Crying rape' and 'Need ideas for blackmailed girl'.

Two of his websites were called 'Hurt 2 The Core' (above) or 'Love 2 The Core', and as a condition of membership people were required to upload a certain number of videos to enter

On these sites, users had access to child prostitutes, images of 'delicious little boys' and 'yummy little girls', and videos of 'sexy little boys'

Boys and girls who were under the age of 11 could be 'rented' as sex slaves from US$4,000 [AU$5,711] and others could be 'bought' for US$10,000 [AU$14,277], The San Diego Red reported.

These prostitution services were operated out of Morelia, Mexico City, Guadalajara and Monterrey in Mexico.

THE DARK WEB EXPLAINED The 'dark web' is a term that essentially refers to websites that are visible to the public but hides their server information, including their IP addresses and identity. By doing this, it proves to be very difficult to find out the owner, administrator or manager of a website. They cannot be found in search engines. Nearly all sites on the 'dark web' use a tool called the 'Tor encryption tool' to keep their identities or location hidden. The 'dark web' should not be confused with the 'deep web', which is a term used to describe all web pages that cannot be found or searched for in search engines. The 'deep web' includes the 'dark web', but also includes user databases (like ones belonging to Ashley Madison), pages locked behind pay walls or password protected. Advertisement

Hurt 2 The Core was advertised on The Hidden Wiki, which can only be access by using an encryption tool called Tor that hides the identities of users.

Graham, who studied nanotechnology at LaTrobe University, first came across websites similar to the ones he would soon be running after hacking activist group Anonymous infiltrated a child pornography website called 'Lolita City' in 2011.

This site could also only be accessed by a Tor encryption tool.

Graham went searching for the websites hacked by Anonymous during Operation Darknet, which was announced on 4chan - a freedom of speech image-bulletin board.

Soon Graham's pseudonym made it onto the FBI's most wanted child sex offenders and after a two-year joint investigation by the FBI, Australian Federal Police, Victoria Police, Canadian police and Europol, 'Lux' was charged with 88 offences last year.

Previously, the 22-year-old said he was not a fan of the fetishes he listed on his site, but he did admit to The Kernel as Lux that he had paedophilic urges as a teenager.

During their investigations, authorities also discovered a connection between Graham, who was a babysitter, and Australian businessman Peter Gerard Scully who has been accused of running an international paedophile ring in the Philippines.

Graham has been linked to Australian businessman Peter Gerard Scully who is up on child sex abuse charges in the Philippines

The 51-year-old was arrested in February on charges of sexually abusing 11 children - the youngest of whom was only 18 months old - and killing another young girl.

Scully is currently being held in a prison in Cagayan de Oro in the country's south.

Graham has also been linked to former Adelaide childcare worker Shannon McCoole, also known as Skee, who sexually abused seven children - six of whom were in his care.

The 33-year-old was the administrator of a global child pornography website, where he uploaded child abuse content, some of which he committed himself.

He was jailed for 35 years by a South Australia District Court judge last month.

Graham is set to be sentenced in the County Court of Victoria on February 3.