Broadcast on BBC One over three consecutive nights in May, Three Girls tells the true stories of “Holly”, “Ruby” and “Amber”, who were victims of child grooming over a number of years and who helped to convict nine men of child abuse offences.

The series received more than 9.3 million requests on BBC iPlayer in May and averaged a consolidated audience of 8.1 million across its three episodes. As well as gaining a large TV audience, Three Girls also won the praise of critics. “Beautifully written, powerful drama,” said the Guardian; “An urgent, astonishingly moving piece,” wrote the Independent.

It was greenlit by the BBC as just an idea – unusual in drama commissioning but “absolutely necessary” for this kind of project, explained Bafta-winning director Philippa Lowthorpe. “It would have been unthinkable to let down the girls, again.”

The drama took four years to research, write and produce, including hours of in-depth interviews with the victims and their families, as well as consultants and professionals who deal with child grooming. 

Maggie Oliver, the detective constable involved in the investigation, was a key figure in brokering the relationships with the girls and the production team. Writer Nicole Taylor said: “We went up to see them again and again – and we listened.”

Lowthorpe, added: “The family trusted Maggie and then trusted us. It was a very slow process, lots of gentle meetings, talking and listening.”

The script was constantly evolving as Taylor felt an “obligation to revise things, to constantly update.

“When I had done a draft, the real people would feed in or it would trigger new memories so I would absorb new information. I had to keep the script alive the whole time.”

The team felt a huge responsibility for the story they were telling. There was excellent duty of care available to the families and girls to assuage any fears. Lowthorpe explained: “Simon Lewis, the producer, and Sue Hogg, the exec producer, were brilliant and there was lots of support from the BBC.”

The important contribution to the process of sexual health worker Sara Rowbotham, who was often on set, was also discussed at the event.

Director of photography Matt Gray discussed his cinematography style, which was designed to bring the viewer to the heart of the story: “We shot on an Alexa Amira – in some scenes, the camera would be very close to the actors, which puts huge pressure on young performers, but they embraced it and were amazing. There were lots of long continuous shots, which is brilliant for actors – they could inhabit their characters.”

Lowthorpe added: “We banned wide shots; we wanted to try something brave and new. We shot it non-conventionally.”

The director revealed that she had looked for actors who had “already acted a little bit, but could also be utterly natural”. Established TV stars Maxine Peake (who played Rowbotham) and Lesley Sharp (Oliver) also came on board and “they were both immersed in the material and so committed to it, which was exciting to witness”, said Lowthorpe.

Editor Úna Ní Dhonghaíle passed on her advice to fellow editors in the audience: “Watch all the rushes. I was lucky, there was a bounty of riches there.”

She talked about retaining the integrity of the piece during the court scenes: “I couldn’t intercut the court testimonies, yet still had to keep the rhythm and the pace, as the veracity of the courtroom and the words spoken was so important to the story.”

The editor’s greatest challenge was “to find a way of editing the material that kept the subjective point of view of the girls alive, so that the audience would understand street grooming and empathise fully with the girls”.

The creators of Three Girls were in conversation with Bristol Centre chair, Lynn Barlow, at the Watershed, Bristol on 11 September.