Keeley Hawes stuns in heartbreaking It’s A Sin finale

After viewing episode five, any doubts will have been quashed, as the Bodyguard star turned in an acting tour de force as a mother whose grief and denial turns her vicious.

*It goes without saying, but major spoilers ahead for the It's A Sin ending*

Beginning in November 1991, the fifth episode reveals that Ritchie (diagnosed with HIV/AIDS in episode four) has been deteriorating in health, while his best friend Jill (Lydia West) is acting as his nurse, keeping up-to-date on his medication and putting him to bed at half seven at night.

Ritchie's parents, Valerie and Clive (Shaun Dooley), have no idea that their son has AIDS, or that he's gay. However, that soon changes when they pay an unexpected visit to London and Ritchie's neighbour directs them to the hospital, where Ritchie has been taken.

Up until now, Valerie has always appeared as Ritchie's sweet-tempered, caring mum, who protects him from Clive's gruffness and occasional outbursts. But in a brutal knife twist, it's Clive who breaks down in tears over his son's diagnosis, while Valerie goes on the rampage.

Emotions flash across her face, from shock and denial to pure, unadulterated rage, her court shoes clip-clipping down the hospital corridors as she demands answers from everyone, everyone, except her son.

The hospital workers are deemed idiots, and a weeping Clive is smacked over the head, but it's Jill who gets the full force of Valerie's grief and anger. When Jill quietly affirms that Ritchie is in fact gay (and not just "randy," as Valerie apparently hopes), she receives a vicious, personal tongue-lashing.

And then Valerie does the unspeakable. She whisks Ritchie away and bans his friends from his deathbed, using the excuse that they've already had "their time" with him.

Roscoe (Omari Douglas) and Jill make the ferry pilgrimage and rent rooms in the Isle of Wight, hoping against hope that Valerie will change her mind. Ritchie (unaware of what Valerie has done) even begs to see Jill near the end, explaining how she understands him.

Valerie eventually arranges a meeting with Jill, but by then it's too late. Ritchie died the previous afternoon, she tells her - and, as Jill deduces, he was alone in his room at the time.

By the end of the episode, it's a testament to Hawes' skill as an actress that viewers will still feel a shred of sympathy for Valerie - even as we're shouting at our television screens.

Valerie emerges as the show's unexpected villain, but, as Hawes herself said in a press Q&A, the character is a "product of her time".

She said: "Valerie is someone who is very easy to dislike and so the trick was bringing something likeable to her because we have to have empathy with her.

"And I do. I knew women like that, I knew people like that. At her core she adores her children and her son. In her heart she adores him."

All five episodes of It's A Sin are available to stream on All4. Looking for something else to watch? Check out our TV Guide.