A serial sex attacker who built dens in the homes of his victims before raping and assaulting them is now eligible for parole, a new documentary has revealed.

Channel 5's new series, The Intruder: He's Watching You From Within, looks at Malcolm Fairley, who committed burglaries and sex attacks across Hertfordshire, Bedfordshire and Buckinghamshire throughout 1984.

Fairley was sentenced to six life sentences for his crimes at St Albans Crown Court in February 1985, but can now be paroled, having seen a bid for freedom refused in October.

He was nicknamed "The Fox", because he would build dens in the homes he broke into while waiting for homeowners to return.

He also prepared and ate meals, watched TV and collected trophies from his victims, before committing crimes including rape and indecent assault while wearing a mask and brandishing a shotgun.

He had committed 81 offences before being arrested at his home in Kentish Town, north London, in September 1984.

The Intruder: He's Watching You From Within, includes never heard before police interviews in which The Fox admits to his crimes and explains why he did them.

Among those interviewed for the documentary was retired Det Ch Supt Brian Prickett, who raised serious concerns about Fairley's possible release from prison.

"Malcolm Fairley should never come out of prison after all the fear and harm he put into the community. He never deserves to be released because I think he's still a real risk to the public," he said.

Mr Justice Caulfield, who sentenced Fairley following his trial at St Albans Crown Court in early 1985, said he had "wickedness beyond condemnatory description", and that he "desecrated and defiled men and women in their own homes".

The documentary has been produced by ITN Productions and commissioned for Channel 5.