Given the capacity of drama to allow people to empathise with others, one interesting question is who you choose as your protagonist. Which made Fiona’s Story particularly interesting, choosing as it did to understand a deeply unpleasant situation from the perspective not of its instigator, but his wife.

Gina McKee was brilliant as Fiona, the middle class mother whose life is thrown into turmoil when husband Simon (just as capably played by Jeremy Northam) is visited by the police regarding the download of images of child abuse. He blusters, stalls, claims that someone has swiped his credit card details, but there’s no getting away from it: Simon has done just what the police said he did. And Fiona has to deal with the implications and consequences of that.

To begin with, Fiona is in turmoil and confusion. She attends a nativity play and doesn’t hear a word, concentrating as she is on the impossibility of what the man she loves has done. And once she’s on that path, she can’t help ask other questions. Why exactly is it that she and Simon haven’t slept together for a year or more? Getting answers isn’t on the agenda though, because Simon has the upper hand, playing emotional games to manipulate Fiona and make her feel guilty. And he succeeds in that, setting her head spinning and feeling bad about herself instead of taking decisive action about her husband, who acts as if he’s done nothing wrong and is supported in that belief by the inconsequentiality of what happens when legal processes slowly creak into action.

Kate Gabriel’s script is strong in depicting Fiona’s erosion. She’s caught in a dismal situation, and in particular the question of whether Simon should be allowed access to their daughters. Simon’s injured face is immensely slappable in the scenes when he’s playing the good father, and his family aren’t much better. His brother pretty much accuses the police of political correctness gone mad for spoiling every man’s right to look at porn, and his mother writes off the situation as a midlife crisis.

No wonder Fiona turns to another man, in the form of the conductor of the choir she’s a member of. Simon is pitiful in his vitriol when he gets wind of this, and petty when he tells his daughters that their mother has a boyfriend. In short order, Simon has a girlfriend, and his daughters and their friends sleep over at weekends. Fiona is put under tremendous pressure, especially when she confides the truth to a friend, who understandably wants her own kids to be let nowhere near Simon.

Fiona’s Story was powerful television, intelligent and uncompromising. The only false note was struck by Simon’s brother and his defence of a man’s right to look at porn, which sounded a bit too much like a political stance than something a real human would come out with. But given the amount of research involved in a piece like this, it’s amazing how subtly written the overall script was.

Armando Iannucci has recently called for the BBC to launch a premium channel, a subject I have no fixed opinion on at this point, beyond thinking we’re already paying for what should be a premium service. And it’s dramas like Fiona’s Story that make a good case for keeping BBC1 just how it is, where everyone can see programmes of this calibre and importance.