Exclusive: When Lucinda Bruce-Gardyne discovered that her younger son was allergic to wheat and could not eat even small amounts of bread or pasta, she was determined to do something about it.

It is a problem for many parents whose children suffer from food allergies.

But when Lucinda Bruce-Gardyne discovered that her younger son was allergic to wheat and could not eat even small amounts of bread or pasta, she was determined to do something about it.

Her solution was a work of Genius - quite literally.

Mrs Bruce-Gardyne, 38, who lives in Edinburgh, developed a gluten-free loaf that impressed Tesco so much that the supermarket giant acquired exclusive rights to sell it.

The loaf, branded Genius, went on sale in 700 supermarkets this week and promises to transform the eating habits of thousands of people for whom everyday foods such as sandwiches are effectively off the menu because the gluten in bread can trigger life-threatening allergic reactions.

Mrs Bruce-Gardyne, a member of the family that owned the famed Lyons Corner House and bakery empire, is a trained chef and accomplished cookery writer, so turned her skills to trying to find a solution to her children's allergies, which meant that meal times had become a minefield.

Her first child, nine-year-old Angus, is allergic to dairy products.

Three years ago she became worried that her younger son, Robin, might also have a serious food allergy when he developed bad stomach upsets after eating bread or pasta.

As his fourth birthday approached, it became obvious that there was something seriously wrong.

"He had no stamina at all. He was very grumpy, very thin - basically malnourished," said Mrs Bruce-Gardyne.

After consulting specialists, who said she should take him off wheat, she decided to try a gluten-free diet.

"Within two months he had put on two kilos and was a totally different child."

Determined that Robin should be able to enjoy foods others took for granted, she decided to try to develop a recipe for a gluten-free bread that tasted like the real thing.

As it is the gluten in wheat flour that allows dough to rise and gives bread its chewiness and elasticity, this was a tall order, as existing offerings were dense and heavy.

"I knew I could improve on the gluten-free loaves on the market," Mrs Bruce-Gardyne said. "I was determined to create a loaf that was light, moist and delicious whether it was toasted or not."

She spent an often-frustrating 18 months experimenting in her Edinburgh kitchen. "My children would come home from school to find 14 different loaves of bread for them to try. I even damaged my oven."

She eventually produced a loaf that delighted Robin, and included the recipe in a top-selling book on cooking for people with food allergies.

When she decided to test if there was a wider market for the bread, the manager of her local Sainsbury's store referred her to United Central Bakeries at Bathgate.

After another 18 months spent fine-tuning the recipe for mass production Mrs Bruce-Gardyne struck a deal with Tesco.

Although the product has only been on sale this week and will be officially launched nationwide on Monday to coincide with coeliac awareness week, she believes she is on to a winner: "We have been getting 50 e-mails a day, and people are saying for the first time in 20 years I have been able to eat a sandwich'.

"The message we are getting is that this is a life-changing experience. People can fit in at lunchtime, and their kids can fit in at school."

She is confident of selling thousands of loaves of Genius weekly. They will retail at £1.99 each until June 7 and £2.49 thereafter.

Plans for other gluten-free products are in the pipeline.

Coeliac disease is an often serious auto-immune reaction to gluten, estimated to affect one in 100 people in the UK.