AMONGST all the twists and turns and, some might say, inpenetrabilities of BBC drama Line of Duty, Sunday night’s episode was a masterclass by creator Jed Mercurio in writing in a way that authentically reflects the racial diversity of the society in which we live.

The series has, over the years, kept it real with it’s representation of cops, victims and criminals from right across the class and ethnic spectrum and rarely written to stereotypes. Its phenomenal success – 9.6 million tuned in for the opening episode of this series, not to mention the many who’ll watch again on iPlayer just to get to grips with some of those inpenetrabilities – reflects this.

In an age when Black actors have sometimes been cast simply to tick a box or to mention in a producer’s annual appraisal, the scene between actors Martin Compston, Shalom Brune-Franklin and Adrian Dunbar in which it was revealed that institutional racism had played a part in a case they were examining, was trail blazing.

They discussed a case where a young Black architect, Lawrence Christopher, had been attacked by a gang of white youths with a history of racial violence and taken into custody where he was mocked by police officers as he died from his injuries.

The character Steve Arnott, played by Compston, turned to his Black colleague and said he was sorry she had “to dredge all that up” and asked if she was okay.

She replied with a barely perceptible hint of pain in her voice: “Custody officers were laughing and making monkey noises while Christopher lay dying. They were all cleared of misconduct, took early retirement for stress…and claimed tens of thousands of pounds in compensation… How could anyone be okay?”

I choked on the power of this scene. DC Chloe Bishop for five episodes has played the almost emotionless foil for some of Steve Arnott’s hypotheses (and a few of her own) and suddenly out of nowhere we are reminded of her humanness and her blackness and her experience and her strength at having to deal with this case.

At last here was a recognition that Black characters could be written to reflect the universal themes and stories that affect us all but that they also have experiences that only they can uniquely reflect or react to. Add to this the fact that Mercurio has based the storyline on the real life events around the murder of Stephen Lawrence by a gang of white youths in 1993, and the death in police custody of Falklands veteran Christopher Alder in 1998, and it’s clear that authenticity is at the heart of this episode.

And authenticity is one of the great aims of diversity. Yes, diversity is also about fairness, representation, and inclusivity but for audiences and TV executives alike diversity brings new stories and crucially, different ways of telling stories.

As someone who has worked in television for 30 years and counting, and been through countless false dawns where it felt like progress on representation was being made after a series of short-term initiatives only to be told an idea was “too niche” or there “wasn’t enough Black or Asian talent out there”, I am convinced that we have now crossed some sort of Rubicon.

After last year’s Black Lives Matter protests, UK broadcasters were swift to act. ITV launched an advertising campaign in support of the dance act Diversity’s Black Lives Matter-themed performance on Britain’s Got Talent. The performance had received 24,500 complaints to Ofcom for being “too political”. ITV’s full-page ads in every newspaper featured a still from the performance which read: “We are changed by what we see. Just as we are changed when we are seen.” Ofcom rejected the complaints.

The BBC has earmarked £100 million of its existing budget towards inclusive and diverse content over the next three years. The money is available to those creating diverse content, diverse production leadership and diverse-lead production companies. The definition of diverse is Black or minority ethnic, disabled and those from lower-income backgrounds. The BBC is also asking all producers they work with to ensure 20% of their workforce are from under-represented groups.

This is a mammoth but top-down effort that will bring rewards for all – for the audience with their ever increasing appetite for content, for the TV industry as a whole, but most of all I think, for those in under-represented groups who never imagined a career in film or TV was for them – the door is open.

When I think of under-represented groups I think of the many schools I visited as a BBC education producer in the 1990s all over Scotland but particularly in places like Castlemilk and Govanhill where few young people would have thought about a career working in film or television because it didn’t feel like the kind of environment for them. That’s the bit of all the high level strategies that really gets me excited and keeps me focussed on the importance of inclusion.

The hope is to make the system – the broadcasting and content creation system – institutionally inclusive where every part of the system is interdependent on another part and all parts are pushing in the one direction towards genuine inclusivity. Once that’s done we can do away with quotas and ring-fencing and initiatives and schemes and just get on with making the most creative content we can from a myriad of different voices.