IN THE run-up to Christmas I've been doing more public parenting than I've done all year. For someone who doesn't leave the house for weeks on end, this can be rather disorientating. It began with the onset of December, when my four-year-old son, as part of his ongoing campaign to break his father's heart, turned five.

Barnaby selected the same venue for his party that every other five-year- old in the area always picks: an indoor play centre under the Westway. It is a children's paradise, full of slides and ladders and webbed-rope walkways, and consequently a kind of parent's hell, and one which smells strongly of feet. The place makes very little concession to adults. One is made to feel like a vegetarian in a steak house. Sitting in a sticky chair, making small talk with other parents, I resisted the urge to apologise. The place is a great leveller, I decided, as I watched fund-managing Supermum Nicola Horlick settle into another sticky chair across the room.

During the party, I tried to tell my Alexander Technique instructor, whose son was among the revellers, the amusing story of how I got the gash across the bridge of my nose, how I was strolling up Portobello Road in the dark, looking at my feet, and walked into a market stall. "Why were you looking at your feet?" he asked. I felt my neck muscles turn to stone.

"You can't just stand there," hissed my wife, when she later caught me ostentatiously exhibiting good posture. "You're the father." I opted to feed the baby sullenly in a corner. Barnaby, for his part, enjoyed himself so much that he was sick on his trousers. That's what I call a party.

Next up came the school nativity play, in which Barnaby was once again the centre of attention, in his role as Narrator #2. I suddenly realised that I was the only Dad in the world without a video camera. The last time I looked, video cameras were naff and obtrusive, and a discreet gun- metal grey stills camera was the only thing to have. Now everybody has a discreet gun-metal grey video camera. The same thing happened to me with mobile phones a couple of years back. I need to get out more.

From the moment Barnaby stepped on to the stage I began to cry. Well, almost. I don't personally count it as crying unless the tears actually roll down the face. So long as you blink them away before that, it's just being overwhelmingly proud. It's a matter of keeping on top of it: blink, smile, look away, blink, look up, blink, smile, blink. It was a long play.