Jonathan Trigell: Get that tree out of my post office

There is a Christmas tree in my local post office. You might think that the most unusual part of that, in these days of closures, is that I have a local post office. But I live in France, where religious symbols are strictly banned from state institutions and so I can't really see how they can get away with it. If you don't think that a Christmas tree is really a religious symbol, ask yourself how comfortable you would feel decorating one in Iran?

Perhaps the eyes of French secularism are elsewhere: focused on schools at the moment, quite rightly. Teenagers don't get away with wearing those chastity rings in these parts. Good. As Marcus Brigstocke put it: "If you want a ring to show you're not having sex, get married like everyone else!" One Christmas, when I was a teenager, a group of my female friends gave each other little chains to wear. They were also virginity symbols, but the antithesis of those popular now. The idea was that the girls would, eventually or shortly, give them to the person who took their virginity. I like to think this made them think a little bit more carefully about who that would be, and maybe even dignify that decision with a sort of ceremony. Though it probably didn't and I never got close to finding out for myself.

Christmas was even more important, of course, as a younger child. I went to a Christian primary school. We all did back then; it was called "school". At Christmas time, we prayed little-children prayers and sang jolly songs about Jesus. We were credulous children and we believed what the teachers told us. We believed in baby Jesus and we longed for Santa's coming. Christmas was a lively, lovely time of year; for me, for most. But the problem is that Santa wasn't as generous with all the children. One year, a girl at my school – the same said to have fleas – got a single, naked, second-hand doll for the entirety of her Christmas spoils. It could almost have been looted from the cardboard manger of the nativity play, except that it was smaller, cheaper and older. This was treated with derision by the rest of us, in carefree, childish, cruelty. If the presents came from Santa – from God by proxy – then "God hates you too" seemed to be the message to her. God hates poor kids. God save the Queen.

Which is strange because Jesus loved the poor: he was mad for them, the poorer the better. He said the rich would never get near heaven. Jesus would not have been keen on the Queen. Jesus had a lot more than just looks in common with Che Guevara: he was a revolutionary; a redistributor. But that's not the holy infant we were taught about at Christmas: the blessed baby with more than his fair share of dads.

Jesus existed; probably not even Dawkins doubts that. But he wasn't really born in Bethlehem. His biographers – various artists, ghost-writing God's bestseller – were faced with a big problem: their boy was very widely and well known as Jesus of Nazareth, but the Prophet Micah specifically stated that the Messiah would be born in Bethlehem. To say that old Joe and his perilously pregnant wife were visiting relatives almost 100 miles away because it was Christmas would have thrown up further queries. So the writer we call Luke invented the only slightly more credible conceit: that the Romans had insisted everyone went back to the town of their birth to be counted, wives in tow. We do the same thing now, of course – en masse, we return to the town of our births every Christmas – and even with cars and trains and planes, the country grinds to a halt and loses millions upon millions in lost work days. But at least now we have the gift-giving industry, which boosts consumer spending in compensation. The Romans were meticulous record-keepers and it is quite clear that no such census was taken. Of course not, since it would have been a doubly pointless exercise: devastating the economy and providing not useful data on where their subjects lived, but irrelevant data on where their ancestral homes once were.

So every year, throughout much of the world, we celebrate a fictional story. As a novelist, I really enjoy that. The quality of writing and characterisation in the Bible doesn't compare to Joyce, but the main event is so much bigger and better than Bloomsday.

I came home, too, last Christmas, to the town of my birth, for the first time in quite a few years. And for the first time since I was a child, I spent Christmas with a child: my nephew, Alex. It was precisely what Christmas should be, full of laughter and innocence, not just whisky and turkey. It was my best Christmas since the year when I got a US cavalry outfit and a rifle and soldiers for my wooden fort and quite a lot more besides, because my parents, both in good jobs, loved me very much. But, more importantly, so did Santa.

Alex believes in Santa and I don't have the heart to dispel that magic. Not only because of the pleasure it brings him, and through him to us. But because I know that one day it will be dispelled anyway. The rumours will come, as they always do, from the older kids. The first trickles of uncertainty will in time lead to a complete debunking of Father Christmas. And perhaps the throwing-off of that early, easy myth is a step on the path of rational thought, of the reasoning which will eventually debunk all the other ' nonsense too. For now, I suppose it makes him happy. But then, he would be happy anyway: the toys and our love would be much more than sufficient. And I still worry that the Santa story, such a tiny, temporary, extra joy for him, must be making other less-fortunate children even sadder.

Either way, Santa should be a home-time pleasure, as should all matters of faith. Religious education is an oxymoron. Instead of building more faith schools we should be campaigning to leave that divisive, dictatorial, genocidal, sod, God, at the school gate. We should be following the French example – they're not wrong about absolutely everything – and keeping out the chastity rings and rosaries and headscarves too. And since here in France those laws already exist – and this isn't humbug, I just hate the hypocrisy – get that bloody Christmas tree out of my post office.

Jonathan Trigell's latest novel, 'Cham', is published by Serpent's Tail