SARAH Hewitt always felt like an outsider at school.

She was disruptive, found it difficult to make friendships, and for years wondered why she did not fit in.

To escape the confusion and angst that beset her days at Bloxham School, near Banbury, she would immerse herself in music, and excelled at the clarinet and saxophone.

It was not until she was 26 that doctors diagnosed her with Asperger’s syndrome, after her mother Sue suspected her daughter’s social difficulties were not normal.

Last night, Mrs Hewitt, who is married to 45-year-old property developer Chris Liversedge, said the diagnosis changed her life, and helped save her relationship.

Asperger’s is a form of autism, a life-long and incurable disability that affects how a person processes information and relates to other people.

Mrs Hewitt, who lives in Stanton Harcourt, said: “Some things had been going wrong for years, and my mum said she thought I had a chemical inbalance.

“I had difficulties in social situations and managing relationships.

“When you get older, children are expected to become more responsible and learn how to interact with other people and how to empathise, but I did not.”

About 588,000 people in the UK are thought to suffer from some type of autism including Asperger’s, but only one in five is female.

Diagnosis so late in life is also rare, with many youngsters showing signs from the age of two.

Mrs Hewitt added: “I would get left behind in conversations and I could not master the skill of making people feel good about themselves or comfortable with me in their company.

“I was too honest about things, I did not learn to ‘white lie’. I was very blunt with people and didn’t realise what I was saying would cause offence.

“My sister and her friends in Stratford always spoke of someone called ‘Orange John’. I really offended him when I met him, as I said, ‘You must be Orange John’, and I did not understand that was not what everyone really called him.”

The 33-year-old dropped out of Goldsmiths University after a term, and began a cycle of different jobs, all of which ended after relations with her colleagues deteriorated.

She has maintained her current role as a senior technical consultant for BT thanks to the support of the company and the National Autistic Society employment arm Prospects.

She said: “When I was diagnosed, it really helped, things made sense. It really helped my relationship with my parents and sister, they realised I wasn’t a nut case, but that my brain was wired differently.

“I do not know if my relationship with Chris would have lasted had I not been diagnosed. He understands it now and my differences.

“He knows if I am behaving strangely I am not doing it intentionally. He is a very patient man.”

She admits that although she has become more aware of herself, she still struggles with “meaningless small talk” and is dogged by obsessive behaviour – both typical characteristics of people with Asperger’s.

She added: “The difficulty is, it is so invisible, Asperger’s does not affect intelligence or the way you look.

“It can be very difficult because people expect you to be the same as them and operate in the same manner, but there are subtle differences which can surprise people.”