Mike Willson is relieved to know he can still do it. After all, 22 years is a long time. But almost a quarter of a century since he was "a plain, ordinary classroom teacher - not a head of department or anything", he has discovered he can still give science lessons that lead at least one student to declare on leaving the lab: "That was (expletive deleted) good science."
Mr Willson is a teacher trainer, a lecturer in science education at Sussex University. But for two days a week throughout this academic year he is swopping jobs with Kevin Hutchings, a science and personal and social education teacher at Seaford Head Community College in Seaford, near Brighton, East Sussex.
The swop comes as the PGCE course at Sussex celebrates its 30th anniversary - the oldest predominantly school-based initial teacher training course in the UK. But the switch - a personal initiative between the two partners - links training and teaching in a novel way. It has put Mr Willson back in the classroom firing line and allowed Mr Hutchings to step off the timetable treadmill to help train tomorrow's science teachers - and given him the chance to develop his own research.
Both men have found the experience instructive. "It's made me appreciate the demands on teachers," says Mr Willson. "During one break I watched a teacher trying to get to the coffee machine. First someone interrupted him for his year-nine assessments, then someone else wanted to know how the moderation was going for GCSE, then another person wanted a special needs statement. He finally got to the machine but then the bell rang. He never did get his coffee."
For Mr Hutchings, who has been teaching for 11 years with time out to study for a PhD, the difference has been in the change of pace, giving him the chance to think. He explains: "At the university you're much more in control of your own time management. I can go in at half past nine at night to do something, if I want to. At school, you start work on something, then you have to stop to do the register or whatever."
More importantly, it has brought the theory and practice of teaching nose-to-nose. One trainee, who was struggling with classroom management, was able to come into the school and watch Mr Willson give a hands-on demonstration in the classroom.
Mr Willson has been able to bring theoretical ideas about such topics as assessment techniques into the classroom and modify them "immediately" if they don't suit the needs of real, live pupils. "Then, he says, "if you're looking at an issue such as concept acquisition, you can bring the trainees into the classroom and show them how kids learn - that it is not just a paper excercise."
Mr Hutchings meanwhile has been able to bring his up-to-the minute teaching experience into workshops and seminars at the university, and to spend time visiting other teacher mentors
in the local training partnership, the Sussex Consortium for Education and Research. He says: "I have gained a much wider experience of the various mentoring methods."
Mr Willson has discovered that today's classrooms offer fresh challenges. He says: "There are many more children with special needs in the mainstream than there used to be." And students with attention deficithyperactivity disorder, he's learned, must take their Ritalin or there is trouble. "And you can no longer rely on telling children that they need to know things to get a job. You have to find other ways of motivating them." Then there are the increasingly stringent health and safety regulations, restricting what science teachers can do. He's also been forcibly reminded of the importance of the basics, such as using seating plans to remember students' names.
Time out of school has given Mr Hutchings a valuable chance to develop a project putting classroom worksheets on the Internet. He says: "Teachers always say they're re-inventing the wheel. My idea is to set up a method for sharing classroom resources and worksheets, so teachers can send me worksheets that I can publish on the World Wide Web. People can then look up what's already been done, personalise it for their own needs and download it.
"It's all about sharing good practice. And it's the sort of thing only a teacher would do - academics aren't used to picking up that kind of need."
He has found colleagues at the university strongly supportive, while Mr Willson has relished the collegiate atmosphere of working with other teachers. Both say the change has recharged their batteries. "Other people seem to think it's had a good effect on us," says Mr Willson. "Unless, of course, they're lying!"
The arrangement has thrown up few logistical problems. Both men have remained under their existing contracts. Existing insurance cover has been adequate, and they have kept in touch by personal contact, phone and e-mail.
Mr Willson teaches across the 11 to 18 range. He says: "It's probably good that we're both chemists, it might have been a bit more disruptive if I'd been a biologist." He teaches discrete modules, so handover problems are few. The school is delighted with the arrangement, and there have been no parental complaints about changing faces in the classroom.
"Look at it this way," says Mr Willson, "if you were in hospital and the professor came in to do your operation you would be delighted. It's unheard of for a professor of medicine to avoid going out on the ward or doing surgery. And look at how innovations in medicine come about. People develop ideas then try them out."
This leads on to what Mr Willson calls the "teaching hospital idea of teacher training". Everyone knows, he says, that teacher trainers are seen in a very different light to practising medical professors - often because they are not active practitioners, and have not been for a long time. They therefore lack the respect
engendered by hands-on experience. "If I couldn't do it in the classroom, why should I be training other people to do it?" Mr Willson asks.
But both men believe a teaching hopital, or teaching laboratory, model of teacher training, where teachers and trainers work closely together in real schools could change all that.
"The best people to train teachers are teachers," says Mr Hutchings. Because of this they will be writing up their year's job swop experience and trying to encourage any new government to think seriously about going down this road for future teacher training.
Further information from Seaford Head Community College, Arundel Road, Seaford, East Sussex