Today it is design and technology, first thing. I shall not be able to get into any of the relevant storerooms because access in period one is always erratic. I conduct a limited woodwork lesson in my overcoat, showing how, if I could get to the tools, I would make a halving joint.

TUESDAY A lot of IT today. One mouse not working, network will not print, one enter key inoperative, too few chairs, two passwords not working and a child apparently suffering from VDU radiation sickness. Can it really be five past nine already?

WEDNESDAY Science. I love science. I am to science what Tommy Cooper was to conjuring. Funny how whenever I heat up a conical flask it ends up looking like a bed-pan for Barbie. The students are late back from house meetings, and halfway through the lesson a third of them have to leave early for the drama trip. Chewing gum up the gs taps means we are low on pressure and I have to abandon the experiment when 150ml of water is still not boiling after the best part of 35 minutes.

THURSDAY A supply day. I always go to junior schools on supply, with an exercise ready for literacy hour, a mental maths book and a whistle. Driving the car off in a different direction every week - new horizons, fresh faces, different staffroom noticeboards, you know the crack.

FRIDAY Another supply day. An inner-city school with 350 pupils - 350 Asian pupils. After the class achieves a 100 per cent score in mental arithmetic, I mark 28 English books and marvel at the neat writing and application to task of a group of Year 5 children. At the end of the day I tell them what complex combination I am going to choose for my Indian takeaway that night. Howls of merriment. They say I am a real cool teacher, but perhaps the takeaway will alter that.

Phil Harley teaches three subjects in a Midlands comprehensive three days a week and is a supply teacher in junior schools for the other two days