I've just been doing a few last minute things in Darlington: bought some new jeans and a copy of Mark Steel's Vive la Revolution, dropped a card into the Furballs' and ran into Sara-Jane Hardy. Town was packed, though not quite so heaving as it was a couple of days ago. Everyone seems to have got the shopping in early this year.

Just a little down the road from the HSBC bank the Salvation Army band was playing. There are some types of faith I have a particular respect for, and the Sally Army's is one of them. They quietly ignore the stuff about enduring suffering in this world in order to guarantee a place in the next. Instead, they do their best to help and comfort those who suffer. They are friendly, undemonstrative, fearsome hard workers.

Down the other end of High Row, standing beneath the market cross, was an altogether different type of Christian. He was youngish, wearing jeans, a leather jacket and an ill-advised moustache. He had a poster slung over the stonework behind him, helpfully reminding us that we're all sinners who should repent and find love and peace in Jesus Christ. In case we didn't notice his poster, he had a mic and an amp and was getting enthusiastically stuck into a prolonged exhortation. The gist of it seemed to be that:

1. We are all sinners
2. We are all going to hell
3. We might squirm our way out of being sent to hell if we all love Jesus.

He clearly believed what he was saying. 'Save yourselves,' was his argument, 'like I've saved myself.'

And within that argument, ladies and gentlemen, is everything you need to know about evangelical Christianity: self, self, self. Evangelicals appeal not to our kindness or our sense of decency, but to the craven desire that exists within all of us for simple self-preservation.

I wouldn't have been annoyed if it hadn't been for the Big Issue seller standing twenty yards away. A young Asian woman, maybe 25 or 26, she was simply repeating 'Big Issue, Big Issue..' in a quiet, desperate, humiliated monotone. Did Mr. Evangelical do anything to help her, or even express his support? Did he bollocks. He was too busy banging on about how everyone should read the Bible. It seems he hasn't been reading his own Bible quite closely enough:

'If thou wilt be perfect, go and sell that thou hast, and give to the poor, and thou shalt have treasure in heaven: and come and follow me.'

But perhaps Matthew 19:21 was missing from his copy, because he ignored the woman and continued to advertise his idiocy to the world. I tried to think of a word to describe him, his particular type of belief and his attitude. 'Selfish', I thought, was close - but it didn't reflect the damage he was doing to the honest members of his faith, the ones in uniform quietly rattling boxes a little way down the road. 'Hypocritical' was better but less accurate, as he clearly lacked the grain of self-knowledge that true hypocrisy requires.

It was another ten minutes before I worked it out. I'd walked away from the town centre by then, down Borough Road, past the Italian delicatessen and the sex shop, towards the quiet, leafy street opposite Polam Hall where I'd parked Maisie. I was a bit surprised, really, when I realised that the word I was looking for was 'evil'.