Dennis Nilsen is asked by the police if he's homosexual. The implication is that Dennis Nilsen engaged in sexual activity with his victims. It's unclear, though.

A pin-up poster is seen in Dennis Nilsen's bedroom but is blurred/out of focus.

Dennis Nilsen describes taking off a victim's clothes and admiring their naked body.

A reference to masturbation is made.

Maybe 15 f words throughout the course if the show

Smoking is very frequent throughout the programme by most of the characters

Dennis Nilsen describes himself and some of his victims using drugs together.