For most children with a severe autism spectrum disorder, the opportunities to form friendships with non-autistic children are virtually zero.

The autistic child’s dislike of anything new, the refusal to hold hands, play games, or leave the house, and the inability to communicate or to copy others’ behaviour, make such situations almost impossible for most parents and carers to contemplate.

So when the TreeHouse school for severely autistic children in North London received a phone call from children at a nearby state school, asking if they could come and play, staff jumped at the chance.

The visit was a huge success and so every week for the past three years a small group of children from Muswell Hill Primary School has visited TreeHouse on a Thursday lunchtime to do what children do best: play.

You may well wonder about the wisdom of allowing children with no experience of disability to play with others who are unable to talk to them or to understand all of what they say. So ask the children.

Aoife Okonedo-Martin, 10, from Muswell Hill, gives the scheme a thumbs-up. “It’s nice to learn from the TreeHouse children. Some can’t do things that we can do, like talk. But you get to learn what they are good at. Some are really good at football. With others, you learn their special [hand] signs for communicating.”

Kim Bluman, 11, says: “You might think you have to treat them differently because they are different. But if you treat them how you would normally treat anybody, then they prefer it.”

The scheme is an example of “reversion inclusion” or “inreach” at its best. Instead of taking the TreeHouse children into the community, the community has come to them.

The benefits are two-way. Alison Squire, joint head teacher of Muswill Hill Primary got involved because she wanted her pupils to learn to be accepting of difference. “The children will take this experience into their lives and any time they come up against prejudice against people who are different, will know to reject it,” she said.

The Muswell Hill children play with the TreeHouse pupils in a well-equipped playground. In addition to forging friendships, they try gently to push the TreeHouse pupils out of their “comfort zone”, by encouraging them to tackle challenging tasks, such as kicking a ball or doing a high five.

Before the inreach scheme, one of the TreeHouse pupils, MacKenzie, 10, would not play on the climbing frame. On the day of The Times’s visit, holding the hand of 11-year-old Frances Cummings from Muswell Hill Primary, she cautiously climbs aboard. Then grins nervously. It is a huge step. Sandra Oberhauser, MacKenzie’s mother, says: “The Muswell Hill children get so much more out of her than I can because she wants to play with them, and wants to play like them.”

The TreeHouse school is a beneficiary of The Times Christmas Charity appeal. Please give generously.