The technique, called 9D Breathwork, aims to reduce anxiety and improve pupils' performance.

The NHS says breathing exercises provide significant physical and mental health benefits, external.

Arthur, 12, a pupil at Thomas Lord Audley School in Colchester, said it had helped him.

"When I get stressed here, I do the breathing methods quietly in the corner, and when I get home, I do them again to keep me relaxed," he said.

The technique also involves sounds and images.

https://www.bbc.co.uk/news/articles/cy8vw5p6g54o