Moments that made the year: Tales of the Unexpected I, or how the Teletubbies caught our critic napping

It is one hallmark of the memorable moment that everyone will be expected to spare a moment for it - that, whatever they are doing, it should be set aside for a while to make space for this unexpected rip in the dull predictability of common experience. In terms of television viewing, one simple test is: does what you are watching give you the impulse to summon others to watch it with you?

There were several such moments in 1997 - some of them bathetic, some of them, it transpired, genuinely historic. But the strength of the impulse itself will not tell you much about the moment - in the sense of weight or seriousness - of what you are watching. If I'm honest, for example, I felt the impulse most sharply one day when I was watching review tapes at home. Coming to the end of one programme, I ejected the tape, and my VCR reverted automatically to the channel to which it was tuned. What I saw was a landscape of geometrically perfect hills dotted with primary- colour flowers and peopled by callipygous space bears, with screens in their fleecy tummies. I watched open-mouthed for a while, dazed by the heady, almost toxic cuteness of the scene, but when a lambent sun appeared, framing the face of a chuckling baby, I had to call for help. Had I first encountered the Teletubbies after their invasion of the general cultural consciousness, I would have been more blase and more evaluative; as it was, this was a moment when - rather like the video machine itself - the critical mind lapsed into idle and something more guileless took over.

There was a far graver occasion on which that took place - though, this time, I was the callee, roused from sleep by the news that the Princess of Wales was dead and stumbling straight for the television to share the sense of stupefaction that the serial should have ended so abruptly. Earlier in the year, Everyman's Diary of a Princess had showed a woman working out how to turn media manipulation to moral ends - offering the titillation of glamour-in-danger as she posed, elegant even in armour, in a minefield.

And though there were other moments of gaping wonder in the year - Portillo grey-faced with shock at his election count, Tracey Emin staggering from the set of the Turner Prize discussion - those were moments that kept only a partisan group or a cultural coterie spellbound. Nothing matched the news coverage of Diana's death, or the live broadcast of her funeral, for its ability to pin almost every kind of viewer to the screen. The quality of what you saw here wasn't the point - rarely can a live news broadcast have stretched so little information so far - but, as you watched, you felt part of a great, still congregation.

The best television isn't momentous in that sense: you couldn't really have shouted "Come and see this" about any individual sequence in Tony Marchant's ambitious Holding On (though it had moments that have left a lasting echo in the mind) or in I'm Alan Partridge (easily the best comedy of 1997). But, while television's contingent moments will always have an immediacy that otherprogrammes find hard to match, they shouldn't make us forget how hard it is to produce something that makes you want to watch week after week, rather than something you simply must watch right now.