The parents of an autistic teenager will call time on years of campaigning on Sunday with a church service and CD launch.

Ivan and Charika Corea, parents of Charin, 17, started charity the UK Autism Foundation in George Lane, South Woodford, in 2000. They have since won backing from successive Prime Ministers, the Royal Family and the Pope for their autism awareness campaigns.

They will hold their 11th Autism Sunday celebrations at All Saints’ Church, Inmans Row, Woodford Green, including a performance from former X Factor singer Scott James.

Scott, who has Asperger’s syndrome, starred in the talent show in 2009 and has contributed to a CD, Autism: The Album, produced by Ivan.

Ivan said: “It’s very exciting, we’re going out with a bang.

“Autism is a 24-hour job. It is extremely hard for parents and carers. We had some fantastic successes but I felt it was time to step back because you can get very tired.”

Prime Minister David Cameron and the Duke and Duchess of Cambridge previously lent messages of support to Autism Sunday, which began at St Paul’s Cathedral.

The Coreas also campaigned for a 10-year action plan for autism, which is a lifelong developmental disability, and launched Autism Awareness Year in 2002 which was backed by 800 British organisations.

Ivan said: “It was the first example of partnership working, before that people were working in silence.”

Charin will lead the congregation in the Lord’s Prayer at Sunday’s service despite his parents once being told he would never speak.

Ivan and Charika will now have more time to devote to him.

Ivan said: “His needs will increase rather than decrease when he turns 18. There isn’t a lot in place for adults with autism.

“They need far more opportunities for young people to get jobs.”

Ivan is in negotiations for someone to take over the foundation and said he will still take part in future Autism Sunday events.

The church service starts at 11.15am.