A split in the spectrum? The ongoing battle to define autism

If someone asked you to think of an autistic person, who would come to mind?

Or Robbie Williams, who has recently revealed he's found out that he has "a bit of autism".

What about someone like 34-year old James Fitzpatrick? He doesn't talk, has a learning disability and needs constant care.

A diagnosis of Autism Spectrum Disorder (ASD) means someone has certain core characteristics including differences in how they communicate and behave. It's an umbrella term that includes people with very different experiences.

In recent years there has been an explosion in the number of people with an autism diagnosis on their GP record. In England, it has gone from just over 700,000 three years ago to around 1.1 million today.

The National Autistic Society (NAS) says "evidence suggests there is a significant underdiagnosis of autism, particularly among women and older people".

But what if some people with a diagnosis aren't actually autistic? What if they've really been misdiagnosed?

These questions largely come from 85-year-old Professor Dame Uta Frith - one of the key figures in autism research since the 1960s.

They go to the heart of a debate that is central to the identity of many autistic people.

Dame Uta says this is about misdiagnosis - people wrongly being told they are autistic.

She is reluctant to say how many people she thinks have wrongly told they have autism: "In my worst moments, I think it's a great number, but in my best moments, I think it is a small number."

Dame Uta is worried that autistic people who need a lot of support are not getting the help they need.

Some autism researchers and charities say her views are "dangerous", "misinformation" and pit "autistic people against each other". Many autistic people are angry too, saying this calls their identity and rights into question.

The increase in diagnoses of neurodivergent conditions such as autism and ADHD, along with a steep rise in people reporting poor mental health, has prompted a government-commissioned independent review that is due to be published shortly.