Everywhere you look, there is rusty, corrugated iron panelling, dust, wooden planks, dust, little shacks, dust, newspapers, old tellies and children. Lots and lots of children, aged from two years old upwards. In the dust.

This must be the dirtiest film set ever to make its way on to BBC Schools’ television. Throwaways, written by Ian Strachan and directed by Kim Flitcroft for Scene, the schools’ drama strand, is set in a children’s shanty town on a big dump outside a city, somewhere, anywhere.

The BBC chose to situate it on an open field outside Gateshead, Tyneside. Nice and green it was, until their set people got hold of it and started constructing a dump on it. It was quite a job, taking over four weeks of bulldozers shovelling a lot of earth around to create hills that were big enough to block out the green and pleasant land.

After that, designers built ramshackle, dilapidated huts. Then came the many lorryfuls of waste, specially imported from Newcastle upon Tyne. So authentic was the creation of this massive dump that the entire set was overrun by equally authentic rats, which had to be quickly dispatched to their Maker with the help of Rentokil.

Not many morality plays are set on a refuse dump-cum-shanty town overlooking Newcastle. But then Throwaways is not your average morality play. Producer Ann Brogan explains the book’s appeal: “Apart from it being a popular reading book among children at key stage 3, one of its prime attractions is that it’s rich in moral dilemmas. Lots of decisions that the characters have to make aren’t clearly right or wrong. Hopefully, the book and film will help develop pupils’ powers of analysis.”

With all the public breast-beating currently taking place about the teaching of moral values, the film has certainly arrived at the right time. But this is a morality play in which there are children who have been born to prostitutes, children who have run away but are not bad, children who create an alternative to the bent world created by bent adults, like the corrupt politican played by Corin Redgrave.

The story focuses on a community of homeless waifs and strays who organise themselves into surrogate families. This world is not a parallel present, nor is it easily located in one particular place. As Ann Brogan points out: “Children in this country don’t live in shanty towns, but they do in Latin America and Eastern Europe.”

The location’s anonymity allows, in her words, “a context in which to discuss social and economic issues, as well as the future.” Both the designers and the extras watched documentaries about street children in Central and Latin America for background research.

Many of the child extras come from Kenton School - a city technology college - in Newcastle. Most auditioned through local youth theatres. Among the children playing central roles are veterans from the Newcastle-based Byker Grove, as well as others who have already made a bit of a career on stage and small screen.

Many have read and enjoyed the book. Dean Cook, aged 11, hasn’t, but thinks “it’s a fantastic script. But some bits are upsetting. Like when Sky (a 14-year-old girl who becomes a mother figure for the younger children) thinks she sees her mum in a shopping mall. She follows her around but when she finally comes up close, she discovers it’s not her. I felt really sorry for her.”

For others, working on the film has given them insights into homelessness - a social problem often hidden from view. “I feel like I know homeless people’s feelings more than before,” one says. “It makes you want to give them money. And it makes you see them as people, not just as ‘the homeless’.”

It has also given these young actors a glimpse of hardcore professionalism, working alongside Corin Redgrave, Siobhan Redmond and John McArdle. But if they have been dazzled by the light, they certainly weren’t showing it as they braved the heat, the dust and the mounds of rubbish to hang about chatting, endure night shots, eat out of trailers and do take after take. In fact, they loved every minute of it.

Throwaways will be broadcast on BBC2 on January 10, at 11.40am.