Autistic children often find it hard to read the expressions on people’s faces. Thomas the Tank Engine’s clear facial expressions and simple storylines are said to help them distinguish between different emotions.

Thomas’ TV show, books and comic strips also assist in teaching colours, numbers and words.

Thomas was found to be the most popular toy in a survey of 750 parents of autistic children. And 40% of the parents said Thomas and his various friends were liked by their autistic children for an average of two years longer than their non-autistic siblings.