The mother of a boy with autism has publicly shared a letter from a teacher praising her son for qualities that the teacher said school tests could not measure.

The inspirational letter from Ruth Clarkson to 11-year-old Ben Twist, who failed the Sats he took this year, listed all the talents and abilities that Clarkson told Ben “make you the special person you are”.

In tears. A letter to my 11 yr old autistic son from his school. "These tests only measure a little bit of you" pic.twitter.com/e9OPECidxX — Gail Twist (@gailtwist) July 9, 2016

Ben’s mother, Gail, from St Helens, Merseyside, tweeted that she was in tears as she read the words: “These tests only measure a little bit of you.”

Clarkson, an assistant headteacher at Lansbury Bridge school and sports college, congratulated Ben on his “attitude and success” in completing the Sats.

“A very important piece of information I want you to understand is that these tests only measure a little bit of you and your abilities. They are important and you have done so well but Ben Twist is made up of many other skills and talents that we at Lansbury Bridge see and measure in other ways,” she wrote.

The examples listed included his artistic talents, ability to work in a team, growing independence and kindness.

Clarkson continued: “We are so pleased that all of these different talents and abilities make you the special person you are and these are all of the things we measure to reassure us that you are always making progress and continuing to develop as a lovely bright young man. Well done Ben, we are very proud of you.”

The post by his mother has been retweeted more than 2,000 times. She told the Liverpool Echo: “Ben worked so hard and sitting the tests was a massive achievement. We knew the results were coming but to get a letter like that – I got part-way through it and I burst into tears.”

Ben, who was diagnosed with autism at the age of five, switched last year from a mainstream school to Lansbury Bridge, whose pupils include children with autistic spectrum disorders, physical disabilities, medical difficulties and speech, language and communication difficulties.

Gail Twist said: “Ben was in a mainstream school all the way through and he had one-to-one support. It was a really good school but the gap between him and his peers just grew and grew. As they were maturing, he wasn’t maturing at the same rate.

“Lansbury Bridge school is a lovely environment where people really do have each individual’s best interests at heart. Ben is sensitive and he does worry about things, and I wish more schools did things like this.

“He is all of the things they wrote about him – he is an amazing person. I think their words will stay with him if we keep reminding him what they said about him. When I told him he said: ‘Wow, do they really think all those things about me?’ It’s just a beautiful thing to do.”