An investigation is under way after a man was hospitalised with an allergic reaction after eating a cinnamon bun.

Sue Lewis bought the bun for her 31-year-old son, who has had an allergy to nuts since the age of two, at The Heritage Bakery in Witney.

She said she always chooses cinnamon buns because she's never known them to contain nuts.

Ms Lewis said: "He has a severe peanut allergy and avoids them at all cost. Unfortunately it seems it may have contained them and were not labelled as having them in the product.

"The sign was a handwritten one on a small blackboard with the words cinnamon bun £2.15 and no sign of any allergen information.

"The reason I felt comfortable buying it was that he’s had numerous cinnamon buns from all sorts of places over the years and not one of them has ever contained nuts."

Her son ate the bun later in the day while she was out and fell ill.

She said: "I came back and he said that cinnamon bun you bought me, I think it’s got nuts in because I’ve had a reaction.

Sue Lewis photographed the basket and tongs in the bakery (Image: Sue Lewis)

"I was obviously very shocked. He’d taken an antihistamine and he’d got one EpiPen but he should have two.

"It became apparent he was getting worse and his throat was closing so we called 111. They said he can use the EpiPen even though it was out of date by a couple of weeks or months.

"But he was getting worse and started to panic so we called 999 and an ambulance arrived in 15 minutes."

He was taken to the John Radcliffe Hospital in Oxford at 6pm on Monday (August 5) and remained there until midnight "suffering several violent sickness episodes and a rash over his body" said his mother.

She added: "It was very frightening. Thankfully he is OK and it didn’t result in a fatality, but others might not be so fortunate.

"I wanted to flag it to ensure no one else is at risk. I just picked up the bun and in normal circumstances I wouldn't ask if it contained nuts because I’ve bought them for years.

"But if you go to a bakers and there’s nothing displayed don’t assume."

Jody Kerman, head of prevention, protection and trading standards at Oxfordshire County Council, said: "We can confirm a complaint has been received. We take complaints regarding allergens very seriously and work to understand what may have occurred, why and what actions are needed to reduce the risk.

"The ability for consumers to receive accurate information on the presence of any allergens in the food they buy, whether by being given information in person, or where there are requirements to label food with such information, is vitally important."

The Heritage Bakery said it is currently investigating what may have happened.

A spokesperson said: "We are grateful for this being brought to our attention so that we can take immediate measures to reduce any risk posed. The welfare of our customers is our biggest priority.

"We understand the importance of having food allergy procedures in place and we have full allergen and ingredient listings for our unpackaged products in all of our locations including markets. This is available to customers on request.

"Our shops and markets have signage to state that our bakery handles, and has present the key allergen ingredients, and to ask a member of staff for full details.

"Any pre-packaged products are labelled in accordance with legislation.

"We will work with Trading Standards to resolve this complaint and would like to reassure our customers that we take food and allergen safety extremely seriously."