Tucked away in the PricewaterhouseCooper report on teachers' working conditions is the sentence that says it all. "In terms of volume of work, teachers' and headteachers' working weeks are more intensive than most occupations with 50 to 60 hours being the norm." Despite the holidays, which, in theory, even out the load, that is why so many teachers feel ground down by the job.
In fact, it is less the sentence that describes the problem of teacher exhaustion than one word: "intensive". For while many are asked to work long hours, few face the demands of the average classroom teacher during that time. I have heard Ted Wragg refer to research on the kind of activity carried out by the average teacher during a lesson. He noted that they make literally hundreds of decisions often in only a few seconds. Not all of them are trivial either. Say the wrong thing, for example, and a confrontation might erupt. Find the right way of asking a question or notice a child that is looking blank and enlightenment can ensue.
To be an effective teacher you need the skill of a stand-up comedian in front of a hostile audience at a gig that lasts six hours. You need to be able to time what you do, set the pace, notice when you've lost the crowd and adapt your material on the hoof. You need stage presence and rapport but more than that you cannot afford your audience at any point to become passive observers - they are part of the act. It is not enough to be an entertaining crowd-pleaser. This is where good preparation comes in. The material needs to be tailored to the children. Taking it off the peg, recycling old jokes, or in this case lessons, is as stale and as flat as the old lags on the club circuit.
And to do all that well is intense. The difficulty is that until you have actually done that week-in, week-out slog, it is hard to describe just how intense it is. When I taught, I used to long for the education secretary of the time to come to my west London classroom and try it for a while. But now we have a secretary of state who really ought to remember the bone-grinding, soul-sapping exhaustion that you can feel at the end of a bad lesson, let alone a hard week or a long term.
But then, she did not work under a zealous Labour government so keen to tell teachers how to do their job. Because that is the other problem teachers now face. It is not simply the work itself, it is the sense of constraint.
Not only do you have to work hard but too often it is on someone else's agenda. Teachers, a conscientious breed, implement what they are asked to do but feel compelled to twist and turn to adapt the Government's one-size-fits-all model to the actual needs of their charges. And that, of course, means more work and stress.
So would the solutions suggested by the report, such as more delegation and use of computers, solve the problem? Perhaps for some, but in a way, they miss the point of what attracts people to teaching. It is the electric buzz of a lesson when it goes well. It is the interaction of child with child and teacher with pupil, the feeling that something has been learned. Where is the long-term satisfaction of writing lessons for someone else to deliver or patrolling classes of children facing a screen?
Above all, teachers need time to stop and think; time to relax and draw breath in the day and time to start enjoying their job again, as opposed to chasing after the latest initiative or change in the exam syllabuses. The pace of life in a school is relentless and the physical demands of standing up in front of a class energy-sapping. I know too many gifted teachers, who love working with children, but who are leaving the profession fed up, not to want one ex-teacher at the Department for Education and Skills to change her mind about working conditions - and fast.
Bethan Marshall is a lecturer in English at King's College, London