I was never a supporter of school uniform when I taught in a more affluent area. I could never see the point. Now I can. I would never argue against it.

Uniform does minimise social differences to some extent. Not entirely of course - there are always different types of uniform. The poor are not merely always with us. They are easily recognised. But a uniform makes it just a little less obvious.

The differences are all too easy to see when the baseball caps and t-shirts come out for charity. Lots of the students in the school only have two outfits. School and home. If the home one is in the wash then they cannot come to school on non-uniform day.

This is what we give for charity: we collect some money but our attendance figures collapse. Naturally the girls from the posher end get very excited.

Suddenly it is all bellies and chests. It is because of them that I now know ripped and frayed jeans are in fashion.

The rest of the school knew this long before me. They also know that a non-uniform day is a fashion parade in which they cannot compete. It is an unequal struggle. They have not got their clothes from the right shop. They feel poor. So they stay at home.

It was never meant to be like this. Charity days were designed to raise awareness, engender a climate of giving, and encourage responsible citizenship. All very laudable. They change the shape of the week by adding a harmless little treat.

But they also fuel uncertainty and truancy. Hardly a week goes by without another request to raise funds by opening up the school to a tidal wave of tracksuits. But I am afraid a level of fatigue sets in. We are wary of them. The pupils want to be part of a national event, to feel that they are doing their bit. They enjoy it. We must not be Scrooge-like and deny them the opportunity. But it is not straightforward.

The kids are always generous, but that is not the point. There are other things that schools can do. Perhaps the charity groups believe they are recruiting the kids to the cause by negotiating this exciting opportunity to wear a Beeny hat all day. But we do not look forward to them.

There are many children in need. They need to come to school. An idea that makes them stay away is never a good one.

Ian Roe is a teacher in north Wales