Best Interests review: This searing BBC excels as it presents you with every parent's worst nightmare

Best Interests (BBC1, Mon/Tues, 9pm), for example, asks what would you do if your seriously ill child was lying comatose in hospital, and the doctors told you they wished to withdraw care?

Would you fight tooth and nail like mum Nicci (Sharon Horgan), despite the signs that daughter Marnie will never wake up, or at best will be seriously brain damaged?

Or would you be more like dad Andrew (Michael Sheen), and be more accepting of the doctors' decision, despite the knowledge that your daughter had so much more life to live?

It's to Best Interests' credit that it never tips the balance one way or the other, never making the most agonising of decisions easy for the viewer.

Throughout these first two episodes, it maintains an even-handedness, seeing the drama through they eyes of Andrew, Nicci and their older – and, let's face it, more neglected – daughter Katie.

From her own point of view, Nicci is simply trying to give her daughter the best chance of a normal life, having beaten the doctors' predictions when Marnie was diagnosed with a form of muscular dystrophy.

“I have spent my entire life fighting. For money, for wheelchairs, for breathing equipment,” says Nicci. “For breathing equipment. For night-time support. For educational support. While those in power have tried to cheat us out of what we really need.”

In Nicci's mind, the fight to keep Marnie alive is proof of her love for her daughter.

Andrew, meanwhile, is shown – right from the off – as someone who follows the rules, who raises all sorts of objections not just to an illicit bunk-up with Nicci in a train toilet, but also to riding their bikes across a car park.

His way of showing his love is by letting his daughter go, in the face of the doctors' dire warnings about any further treatment.

“Increasing medical intervention will have less and less impact on her life expectancy,” they say. “More importantly, they will hurt her.”

As the drama continues, the piercing script by Jack Thorne (His Dark Materials, Kiri) peels back the layers of Andrew and Nicci's relationship with each other, and with their two daughters.

Horgan gives Nicci a tigerish single-mindedness, something which has been invaluable in giving Marnie a life she might not otherwise have had.

But what this drama dares to do is wonder if this also denies Marnie the peaceful, loving death she deserves.

And while Sheen portrays Andrew as deeply empathetic, and clearly torn apart by the awful dilemma he and Nicci face, he is a passive aggressive nightmare, content to let Nicci take the lead, and rarely questioning the doctors.

“Just don't make me the unreasonable one,” Nicci fumes at him. “You do that, and I hate it.”

All the while, external forces circle the family, making them doubt their decisions, or entrench their positions.

There's the media, with its incessant phone-ins, polls and 'what do you thinks?', picking them apart with vulture-like cruelty, giving the public the idea that everyone is invested in the situation, and everyone has their own right answer.

And religious groups step in, pledging to fund a legal case against the hospitals to continue care for Marnie, weaponising the family's emotional turmoil, and removing Marnie from the centre of it all to the margins, depersonalising her with ideology and the need for some easy publicity.

“Oh, it's a case now, is it?” worries Andrew.

It's terrific television, grappling with a literal life and death decision with admirable balance and restraint, but it is never dull, worthy, or mealy-mouthed.

The only question that remains is how can you afford to miss it?

Michael Sheen was in another BBC show this week, as Staged (BBC1, Weds, 10.40pm and iPlayer) returned for a third series. Things have moved on from the lockdown-set Zoom calls and into mockumentary. The jokes are wearing slightly thin, and it’s all a bit self-referential, but Sheen and David Tennant send themselves up gloriously.

FUBAR (Netflix) is a vehicle for Arnold Schwarzenegger’s action-comedy schtick, and it’s a perfectly serviceable way of passing the time, but Arnie – although he’s still in good shape – is getting a bit geriatric for this kind of caper, and it never really touches the heights of his True Lies peak.