Despite being a TV critic, I don't watch a lot of the stuff. I'll study the listings and pick out the good bits but I never have the thing permanently switched on, burbling and flickering in the corner of the room as it always was when I was younger.

Growing up, the evening could be timetabled by TV. If I was in trouble and hiding out in my room, the theme tune to Coronation Street warbling under my door told me it was safe to dash to the kitchen for toast because the parents would be safely occupied, and when I was younger still the tune to MASH meant it was time for bed.

TV was never anything other than a method of calculating when the path would be clear to make some hurried toast or noodles without encountering a raging parent on the stairs. Even now, the sight of crooked Northern chimney pots can make me ravenous.

So what is TV for? Entertainment? For education? To break the silences of long, wintry evenings stuck at home? Until quite recently, I'd always assumed it was the latter - just a way of passing the time - but this isn't a unique snobbery of mine because The Eichmann Show (BBC2) tackled the same subject, demonstrating that, back in the 60s, TV was purely for shovelling entertainment at the square-eyed masses, hooking them with flashes and bangs and monsters, and ensuring they kept tuning it to see what happened next week with silly and improbable storylines. TV was infantile. It was something to chew your dinner along to. It was just a way to aid digestion.

So when TV was forced to grow up - to push aside cowboys and aliens and flowerpot men - and broadcast the trial of Adolf Eichmann, it was a huge event, full of risk and awesome responsibility.

Martin Freeman plays Milton Fruchtman, the American TV producer granted permission by the Israeli government to film the trial which will be broadcast in 37 countries. Freeman plays him rather like Woody Allen: small, nervous, fidgety, weighed down by huge glasses and that Noo Yoik accent. He hires Leo Hurwitz (Anthony LaPaglia) as director, despite him being blacklisted back in the US. Hurwitz arrives in Jerusalem to start work on 'the trial of the century' only to discover there's no permission to film. The government gave their blessing, but the judges have the final say. They don't want cameras involved, thinking that having cameramen scattered across the courtroom, trailing cables and hoisting machinery, will detract from the gravity of the proceedings. TV will trivialise it. TV is about cowboys 'n' Indians and cartoon mice.

Fruchtman, quietly desperate, and Hurwitz, smoking and sulking, convince the judges that the show must go on. Eichmann should be displayed, and the survivors' testimony must be heard. For that they must permit TV in their courtroom because 'without publicity there is no justice'.

Fruchtman and Hurwitz start out as partners, working together to bring the trial to the world, but tensions soon spark between them. Fruchtman wants showmanship and drama, whereas Hurwitz wants his cameras to linger on Eichmann's face. Was that a smile? Was that a flicker in his eye? What was that twitch in his cheek? Is he sorry? Is he human?

Fruchtman orders the cameras away from Eichmann's expressionless face. He wants drama, and Hurwitz roars that this isn't a soap opera. Fruchtman retaliates, saying people won't watch unless we give them excitement. They won't appreciate Hurwitz's obsession with Eichmann. The crowds watching at home or in the bars want action. When a witness faints and crashes to the floor, Herwitz's cameras miss it as they were focused on the man in dock. And here's where the tension exposes itself, between the two men, between the two ideas of what TV is for: to educate and enlighten or to simply entertain and engross.

When news breaks elsewhere of Yuri Gargarin, Fructman worries that they're 'losing the audience'. How can the legal jargon of a trial compete with the world's first spaceman? He wants the trial to hurry along to the witness testimony because when the survivors limp to the microphone and start talking of gas chambers and sealed vans then he knows the channel-hoppers will stay tuned. This is distasteful but it's true. It's human nature. We want to hear the bad stuff rather than the serious stuff. And so he and Hurwitz eventually manage to unite: they both want the audience glued to the screen, but Hurwitz wants Eichmann to explain why, whereas Fruchtman wants the survivors to describe how. A balance of explanation and titillation.

Either way, human nature doesn't change. The programme seems to hint at this when a Nazi tries to assassinate Fruchtman in a suicide bombing. As he's dragged away he shouts 'Heil Hitler' and in his murderous fanaticism and warped worship there were echoes of modern terrorist attacks.

Underlining that hint to modern religious extremism the programme ends with original footage of a reporter warning that those who allow skin colour, face shape or beliefs to alter their judgement of a person has already known the loss of reason that Eichmann experienced.

It's a warning, as is the whole programme, not just about extremism and hatred, but about the banality of evil and the frivolity of people.

Of course, Hurwitz doesn't get his wish. Eichmann never breaks down and never explains. 'How can you just sit there?' Herwitz says to the screen, watching the Nazi in the dock. 'What the f*ck are you?' We never find out. It has to be sufficient that he is found guilty. Justice was done and TV allowed us all to see it and, crucially, allowed the survivors to tell their stories at a time when people were often disbelieving, refusing to accept that such a thing as the Holocaust could happen. And there we end with yet another warning, another chilling reminder that history repeats itself.