SOMETIMES I think the weeks leading up to Christmas bring surprises as enjoyable as any we'll unwrap tomorrow.

It's a time when the world still seems to take to heart Dr Johnson's advice, given in the eighteenth century: "A man, Sir, should keep his friendship in constant repair." Not, as I understand it, repair in the sense of making up any quarrels but in the sense of keeping, say, a garment in good condition. I am also un-PC enough to accept happily that "man" includes us women, too.

Christmas cards and letters are a very important part of the repair kit. Even just an annual communication keeps friendship in repair across years and miles.

I had proof of that with a surprise - almost a shock - the other evening. Called to the phone, I found myself talking to a schoolfriend I hadn't spoken to for at least 40 years. And you couldn't hear the join.

Over those years, I'd had news of her from other friends and, for a time, from her mother. I wrote, and had a reply, when her mother died, but we didn't start Christmas correspondence until about ten years ago, when she was in the Far East and I was organising a reunion.

An old and, by then, rather threadbare friendship was quickly repaired and strengthened by photographs. It's now in even better nick since news of local events and people in my letter this year prompted her to ring me, although she'd already sent her own budget of news, complete with up-to-date pictures of the grandchildren.

This year, too, what I thought could well be an unpatchable hole proved not to be a hole at all. Last year, the annual, wryly humorous look at old age, his wife, their children and their children's children taken by a family friend in his Eighties didn't arrive. So, he was 80-odd, he might be too ill or, worse, beyond conventional communication, but surely someone would have got in touch to explain why the hole had appeared.

I didn't like to write this year, just in case, then his 2004 repair kit arrived, humorous as ever, and mine was so gladly written in return.

I haven't seen that particular friend since I was 13 and he was actually a friend of my father from his naval days who asked me to stay in touch after Dad died. Obviously a man who heeded Dr Johnson and, equally obviously, I have to have a soft spot for the man who made me my doll's house.

On December mornings, even if it is fairly late in those mornings with today's postal system, we know the letter box will flap and a card, maybe with a letter, too, will put a stitch in the fabric of a friendship made decades ago, or just last year.

I hope you all have a wonderful Christmas, with your friendship in excellent repair.