He also pleaded guilty to four counts of accessing and transmitting child abuse material.

Before prosecutor Marty Aust read out the agreed facts of the charges, NT Chief Justice Michael Grant urged the public gallery, security staff and media to leave the court.

"These facts contain material that can only be described as grotesque and perverse acts of cruelty which is confronting and distressing and which in my assessment have the potential to cause nervous shock," he said.

"Either way I'll leave that up to you, but the potential has been described."

Details of the offending are too gruesome to be published but resulted in the death of 39 dogs.

"The offender has had a sadistic sexual interest in animals and in particular dogs," Mr Aust said.

As well as torturing his own dogs, Britton sourced other canines off Gumtree Australia from unsuspecting owners in the Darwin region.

"(He) often built a rapport with the dog owners in negotiating taking custody of their animals, many of whom had to reluctantly give their pets away due to travel or work commitments," Mr Aust said.

The former academic, who once hosted legendary broadcaster and biologist David Attenborough, would share videos and images of himself sexually exploiting the dogs on online forums under pseudonyms.

A video was eventually sent to NT Animal Welfare Branch and passed on to NT police who arrested Britton in April 2022.

He has been remanded in custody since then.

Britton was a prominent NT crocodile expert and a senior researcher at CDU.

None of his offending is alleged to have been against the reptiles.

His matter is set to return to court on December 13 for sentencing submissions.