Line of Duty series six concludes Sunday 2 May at 9pm on BBC One.
While the BBC crime drama is fictional – AC-12, for example, is not a real anti-corruption team – the show has taken inspiration from a number of real life cases over the years.
The BBC later apologised publicly for causing distress to the singer, with Richard suing the BBC and winning £210,000 in damages.
The central premise, looking into a police department that investigates corrupt police officers, was explored in a new BBC documentary series titled Bent Coppers: Crossing the Line of Duty.