Gladys Johnson, who had not set foot in a swimming pool until 10 years ago, completed five lengths of the town's swimming pool on Thursday to raise almost £800 for the Autistic Society.

The pensioner came up with the idea as her 10-year-old great-grandson James suffers from autism.

"He lives in Newbury now," she said."But I wanted to do something for the people who live in this area.

"I wasn't sure exactly how many lengths I had done – I had to have my neighbour there to count for me because I was so nervous."

The achievement was even more special because Mrs Johnson suffered from a fear of water until she was 80.

"I had to overcome it to swim," she said. "The staff at the pool have been fantastic and I am very grateful for all their help."

Even now, Mrs Johnson is still very nervous when she swims but finds the water therapeutic after hurting her back.

Although she has no plans to mark her next birthday in the pool, the pensioner is looking forward to going on holiday to celebrate her latest milestone.

Originally from Middlesex, she has lived in the Mildenhall and Lakenheath area for more than 30 years and used to be a familiar face on the local bowls scene.

"I used to play quite a lot of bowls," she said. "I was Suffolk ladies president but now I try to enjoy my time in the water."

She will present her cheque to a representative of the Autistic Society at the swimming pool next Friday.

"We are all extremely grateful to Gladys for her fantastic fundraising efforts and for choosing to support our adult services in Mildenhall, especially as there is such a need for improved support for adults with autism," said Alice Ridley from the society.

"Autism is a serious, lifelong and disabling condition, but the right support at the right time can make an enormous difference to people's lives."

For more information, log on to www.nas.org.uk.