A woman with a little-known condition that can lead to bowel cancer raised awareness and £500 for the disease with a five kilometre sponsored swim.

Charlotte Ward-Perkins, 51, decided to take up a 200-length challenge at Oxford University pool to draw attention to Coeliac Awareness Week, which runs until May 25.

The mother-of-two, who lives with her husband Alistair Gray and sons Archie, 17, and Johnny, 15, in Minster Road, East Oxford, was diagnosed with coeliac disease in 1999 after being referred to the John Radcliffe Hospital with another stomach complaint.

The condition is caused by an intolerance of gluten an element of wheat flour which damages the lining of the small intestine and prevents fats from being properly absorbed.

Common symptoms include irritability, gut pain, fatigue and diarrhoea or constipation.

After Ms Ward-Perkins was diagnosed, family screening showed her mother Bridget Heuston, 88, and son Archie also had the illness, and had to start a strict diet without any wheat products.

She said: "During the last seven years things have changed a lot and people are much more aware of the condition, but the purpose of Coeliac UK's campaign is to make GPs aware of it too, because it can still be quite difficult to get the simple diagnostic test.

"There are over 500,000 people unaware they have the condition several hundred people in Oxfordshire alone.

"My son and I were lucky not to have become too ill before diagnosis. If it goes undiagnosed for a long time, particularly in older people or men, you can develop small bowel cancer."

As well as completing the swimathon on Saturday, Ms Ward-Perkins is compiling a quick reference guide and cookery book, called The Gluten-Free Glutton, to help coeliac disease sufferers find basic wheat-free ingredients.

She explained: "Things have changed enormously over the last few years and most foods now have to specify whether they have wheat or gluten in them. The real problem is you have to check everything you eat, because even small amounts can affect you.

"It's very frustrating for Archie as a teenager. He's limited about where he can go to eat. Most places that do gluten-free dishes, like Petit Blanc and La Tasca, are quite expensive.

"He can't go for pasta, for example, and even though he is supposed to be able to eat things like chips, he has to check they haven't been cooked in the same fat as anything with gluten."

The swimathon was a real challenge for Ms Ward-Perkins, who only recently started swimming regularly.

She said: "This was the first time I attempted a really long swim, and staff at the university pool have been very helpful, allocating a lane for me.

"I wanted to support Coeliac UK. They've done a lot, particularly in the last year, even though they're a very small charity and members don't have to pay to join."