I didn’t think Trash would be the book to get me into trouble. My previous books include references to alcohol and children smoking, so I braced myself for a bit of stick there. I thought that would cause upset among puritans. But when Blue Peter objected to Trash, it was a bolt from the blue.

I teach English at an international school in Vietnam. It is supposedly everyone’s dream to make enough money to get out of teaching, but I don’t buy that. My novels have done well enough for me to be a full-time writer. But after the intensity and sociability of teaching, I found the very private world of fiction difficult. I got back into teaching again very quickly. Trash was written over an intense period over my summer holiday.

When Trash was shortlisted for the Blue Peter book award last year it was a huge honour. Blue Peter was one of the only watchable things on in the afternoon in the late 1960s and early 1970s, and my age group was completely addicted to it.

Then, about a week later, my agent called me and said: “We’ve got a problem.”

In one scene in the book, a couple of policemen are trying to uncover information and are convinced a Filipino streetboy knows more than he is saying. They hold him out of the window, and he is looking down from the sixth floor at the trash bins below. The boy manages to cling to his lie, and the police give up on him. Then one says: “What a piece of shit.” People treat this streetboy as refuse, ultimately dispensable. It’s an important moment.

But the Blue Peter judges said the book should not have been shortlisted because it contains scenes of violence and swearing.

Blue Peter used to suggest that if we all saved our bottle tops world poverty would end, famine would be solved. I think that was a massive disservice to children’s education: the world is more complicated than that. So I think they missed a trick with my book.

As a teacher, I always long to create environments where children are having fun. So much of that is about taking risks. Kids know when they are being patronised, when you are saying: “I can’t teach you that because it will give you nightmares.”

I don’t want to burst anyone’s bubble, tell them Father Christmas doesn’t exist. But there comes a point when you tell kids that when someone says, “everything is going to be all right”, that isn’t always the case. Fiction plays an enormous part in showing the unpredictability, the untrustworthiness of life.

Of course, I’m aware that children’s fiction needs careful editing. Trash takes the reader into a very real and dangerous world. But there is a fierce moral movement to the novel as well. The boys are taking on the power and system of their government. There is a thirst for opportunity, a desperation to climb out of the closed prison of their world. Trash is about how children can grow and transcend obstacles in their way.

That is why it seemed so odd that Blue Peter - a programme that normally champions these things - has decided to be the voice of old-fashioned censorship. I thought: “Surely it’s a misunderstanding.”

There were big guns fighting on my behalf: the head of Random House children’s publishing. But Blue Peter clung to their position, claiming the initial judging was a mistake and the book was “not appropriate for children as young as six”.

I was staggered by this. All Blue Peter did was demonstrate how massively out of step it is with the modern world, with what children, parents, teachers, librarians want. I’m not watching the programme any more. I don’t have a Blue Peter badge, but if I did, I would have sent it back.

Andy Mulligan was talking to Adi Bloom. `Trash’ is published by Random House children’s books.