Research on autism in adults has shown that people with a severe learning disability are more likely to have the condition.

The study, by Terry Brugha, professor of psychiatry at the University of Leicester, involved a survey of adults on learning disability registers in Leicestershire, Lambeth and Sheffield.

The research was carried out between August 2010 and April last year.

Dr Brugha, who is also a consultant psychiatrist with Leicestershire Partnership NHS Trust, said: "We were surprised by how many adults with moderate to profound learning disability had autism because previous estimates pointed to lower rates.

"Our finding that about 60 per cent of men and 43 per cent of women with profound learning disabilities have autism has never been shown previously."