Having beaten nine schools in a regional heat they, along with 82 mainstream peers, are looking forward to the final on Monday of Rock Challenge - a competition designed to show young people that they can have fun without drink or drugs.
"Parents were saying that for the first time they felt like parents of children rather than parents of children with autism," said Caroline Day, a team leader at the unit who co-choreographed the piece with dance teacher Emma Parr.
"One of our children who does not usually talk is now singing at home every day. His mum says he's a different person. She wrote to us and said the regional heat was the greatest day of his and her life. She said she would never underestimate her son again, because she hadn't thought he would be able to do it."
Autism is a developmental disability which affects people's ability o communicate and relate to those around them. Yet the children at Lord Williams's were keen to talk about how much Rock Challenge meant to them.
"It's the best, it's cool," said 12-year-old Hayley."I like the dancing and I'm looking forward to the final, but I'm a bit nervous."
The dance, The Power of Compulsion, was set to contemporary music and was inspired by the everyday experiences of the autistic pupils.
It is the third time that Lord Williams's school has entered Rock Challenge, but the first time that autistic pupils have taken part and the first time they have made the final, which takes place in Portsmouth. The school, which has just been granted sports college status, has more than 2,000 pupils, including 30 with autism who are supported by the on-site Chinnor unit. Those children whose autism is less severe are taught in mainstream classes.
Head Mike Spencer said that the project typified the school's approach to inclusion."They (autistic children) don't command a second glance. It's all part and parcel of being here."