For some people their magical piece of Christmas television is a rerun of an ancient Morecambe and Wise Special, Eric's wobbling glasses making them laugh so much they spill their sweet sherry all over the settee; for others it's The Great Escape, perhaps a special director's cut where Steve McQueen actually manages to get his motorbike over the wire to freedom this time, with Donald Pleasance riding pillion and reading the map with perfect eyesight.
For me, and I am sure that I'm not alone, the magic comes from a 26-minute animated film, first aired on Channel 4 in 1982, and which has been shown endlessly ever since; indeed it's on this year on Christmas Eve at five to two in the afternoon and I, for one, will be sitting down to watch it with my handkerchief at the ready for the moment when I inevitably begin to blub.
The Snowman, adapted from the 1978 book by Raymond Briggs, is a simple story that has the resonance of a fairy tale or a myth; it's one of those stories that seems timeless, as though you knew it already from your grandmother's knee. Essentially it's a narrative of love and loss and, as somebody pointed out on TV the other day, it's an unusual children's story because it has a sad ending.
In the film a boy makes a snowman that comes to life; they have some adventures together, eventually flying over the beautifully-realised Sussex countryside to the North Pole where they meet Father Christmas and then, because dawn is approaching, they fly back and the boy goes to bed and The Snowman takes up his place in the garden.
The next morning he rushes out to play with The Snowman again but sadly he's melted away to a small hill of snow with a hat perched on top. A lesson is learned by the boy and the viewer: nothing lasts for ever, love is fleeting, grab joy while you can before it falls to pieces in your hands or in your back garden. The music swells.
Excuse me while I grab my hanky.
The opening of The Snowman is rather odd; we see David Bowie, dressed as though for a long winter walk in the park, walking in to an attic and introducing the film. My kids were always a bit confused by this, as was I.
Was he meant to be the boy, James, as a grown-up? Was he meant to be an older brother? Was he just a thin bloke who lived in the attic?
Watching it in the late 1980s, I also had an odd memory of a different beginning without Bowie. I later found that in the first showing, Raymond Briggs introduced it, which somehow seems more apposite.
The music, of course, adds to the almost mystical nature of the film; I was once with its composer, Howard Blake, in a lift and I was as tongue-tied as a teenager standing next to Take That.
There were so many things I wanted to say but I couldn't about the poignancy of the music and the way it reflected the animation perfectly and the fact that I wish I'd written Walking in the Air which Bangor Cathedral choir boy, the angelic Aled Jones made famous but which was in fact sung on the film by a choirboy called Peter Auty. Howard got off at the third floor and I remained as silent as The Snowman himself.
One Christmas Eve in, I think, 1985, I sat down to watch The Snowman with my daughter, Kate, who would have been two at the time. We both sat enthralled at the film and that began a tradition that I've tried to keep up ever since; I watched it with my other two kids and then, in a special moment that I think I appreciated more than he did, I watched it with my grandson Thomas when he was probably too young. Still, it made his granddad happy, despite the tears.
My tears, not Thomas's. He says he prefers Father Christmas and, if he's really pressed, he prefers Toy Story but Thomas is young and in time I'm sure he will learn the error of his ways.
These days, of course, I can watch The Snowman any time on DVD; I could watch it in August if I wanted to on my laptop by the poolside somewhere hot, sipping something cool, but that's missing the point.
The Snowman should be compulsory viewing every Christmas Eve in the early afternoon, just as it's beginning to get dark and cold. We should all watch it to celebrate innocence and hope and wonder and the transcendental beauty of scarves, stripped pyjamas, dressing gowns and noses made out of fruit.
Merry Christmas! Happy Snowman!