TreeHouse was founded ten long, long years ago.

One of our first homes was in a room in a public library in Swiss Cottage. "Autistic children in a library" should be a well-known phrase or saying, meaning something like "bull in a china shop", and the ludicrously inappropriate setting gives some idea of the desperation of the parents involved.

There were five children in the ‘school’ then, and the parents of these five children, my son Danny among them, were experiencing the trauma that all parents of a child with a severe disability will recognise.

Our kids were all young, which meant that they had been diagnosed only very recently, if at all, so we were all still grieving for the loss of the children we had all presumed we would be raising. When we did eventually get to talk to professionals about the kind of education that was on offer, we felt that our children deserved more.

Autistic children need specialist education, but at the last count there were just 7,500 specialist school places in the UK for ninety thousand children. These are lottery odds -- the TreeHouse parents decided to make their own luck.

The most common description of autism is that it is a communication disorder, but that doesn’t really even begin to explain it. A communication disorder sounds like something you have after a particularly gruelling afternoon at the dentist and your mouth is swollen. But a child with autism cannot communicate with you, and neither you nor anybody else can communicate with him, either verbally or in any other way. That means he, and it usually is a he, cannot learn how to talk or understand even the simplest things about the world.

In any case, that description ‘communication disorder’ cannot convey some, most, aspects of the condition that make the lives of parents and carers so difficult on a day-to-day basis.

It doesn’t convey the inexplicable and sometimes violent expressions of distress, the morale-sapping repetitive behaviour, the sleeplessness, the refusal to play games or leave the house or be in the same room as others - the refusal, it seemed to us sometimes, to do anything much at all.

Children with autism need to be taught in painfully small steps, and the method of education we wanted for our children recognised this. Because Danny has this condition, he couldn’t copy, and because he couldn’t copy, he couldn’t learn.

His education began with him learning to bang on a table in response to someone else banging on a table. This may not seem like much of an achievement, but for us, Danny’s parents, and for parents of any child who is severely autistic, this was a major milestone, a breakthrough more fundamental than learning to read and write.

Ten years ago, I couldn’t see TreeHouse lasting. The room in Swiss Cottage library seemed to me to be a stop-gap short-term solution to an intractable and depressing long-term problem, and I had no idea what we were going to do afterwards. I had, however, completely underestimated the determination and ambition of the other parents involved, and to my amazement, the ‘school’ became a real school, no speech marks necessary.

We employed amazing teachers, and then an indefatigable director of development. We moved out of the library and into a private house. When we got thrown out of the house, we moved into portable buildings on land owned by the Coram Foundation. As we started to accumulate children, the portable buildings got bigger. Eventually we bought our own plot of land, and set about raising the money to build a permanent school on it.