We caught a rat in our humane trap this morning. In a space no bigger than two loaves of bread he ran around in small circles, shrieking, until we liberated him into the nearest stubble field, from which he will no doubt return to raid our chicken’s feed store.

I’m with you, rat. I know how it feels to run around in circles yelling defiance - inwardly, at least. The problem is, my cage is a tighter fit than yours.

We have reduced permanent exclusions at our school to zero. But to keep in school those pupils whose lives began to go off track the moment they were born into poverty and social dislocation takes a shedload of hard work and money.

Nationally, more than 5,000 young people are permanently excluded every year. My school doesn’t add to them any more. But my local authority “improvement adviser”, glancing at our figures, said: “Ofsted doesn’t like to see that. It looks as if you artificially inflated the figures to get the drop.”

I am starting to see the bars of the trap.

As head, I am responsible for all my pupils. I do not exclude because I know that only 1 per cent of permanently excluded children achieve five A*-C GCSE equivalents, since there is nothing out there for them and the pupil referral units are not working despite the dedication of their staff.

I also know children are much more likely to be excluded if they have special educational needs, their family is poor or if they are in care. But you keep these sort of children in school at a heavy cost in time, resources and to the school’s reputation.

The trap is closing.

So we no longer permanently exclude pupils. At my school, behaviour is pretty good overall but it still takes endless hard work in classrooms. Teachers have to manage children whose behaviour, on occasion (depending on what dad has done to mum or boyfriend has done to mum, or what mum has been popping or drinking the night before), is off the scale. At the same time they have to teach the others.

And heads have a duty to protect “the others”: the vast majority of pupils who are loved and supported by their families, as well as those who are not so supported but somehow transcend their home lives and want to succeed.

Then you deal with the parent who says: “I didn’t bring up my child to behave like that. Why should they be in classes where others do?” I don’t have the answer.

The trap shuts.

You are caught between the demands of a dysfunctional inspection system, the rights of the disadvantaged and the entitlement of the majority.

But at the end of each working day I go free. My analogy is all wrong: it’s not me who’s in the trap, it’s the excluded children. And they’re not getting out.

The writer is a headteacher in the East of England. To tell us what keeps you awake at night, email david.marley@tes.co.uk.