A Lewisham mum whose son suffers from severe allergies has said she is “lucky” he is on the mend after having an acute reaction to a McDonald’s burger.

Natasha Tourmentin, 24, told News Shopper her four-year-old son Leo was violently sick after taking a single bite of the burger, which she believes contained traces of cheese.

Leo is severely allergic to eggs, milk and nuts, which means Miss Tourmentin has to take extra care over what he eats.

“It plays havoc with his skin. He gets bad eczema,” she said.

Last month, when Leo was in hospital for an allergy test, Miss Tourmentin bought him a burger.

“He was just refusing to eat anything. He only wanted McDonald’s.”

The mum, who is studying beauty at Bromley College, went to the Lewisham branch of McDonald’s and explained his cheese allergy to staff.

“I even checked the allergen book in there. They gave me a plain burger with ketchup and gherkins, which he can eat, so I gave that to him.”

However, when Leo took a bite of the burger, he was sick several times. Miss Tourmentin and her mum then checked the burger and could taste cheese.

She believes the burger she was given had originally contained cheese, which had been taken out by staff before it was served up.

After Leo’s extended stay in hospital following the reaction, Miss Tourmentin complained to McDonald’s – but had to wait a long time for a response.

“I called into the branch when it first happened and he was still in hospital and they said they would investigate it. It took them over two weeks to respond and it was such a half-hearted apology. They gave me £20 worth of vouchers.

“It’s not good enough. It could have cost somebody’s life,” Miss Tourmentin said.

She added Leo was “lucky” to have already been in hospital when he reacted to the burger, and has called on the fast food chain to take allergies more seriously.

“If you’re working in a restaurant, you don’t have the option to not know about allergens.”

Miss Tourmentin, who often takes her son out to eat, claimed she has never had a problem with independent restaurants - which always cater for Leo’s allergies.

She also slammed criticism she has received for giving her son McDonald’s food.

"Why should he miss out because he has allergies?” she argued.

A spokeswoman for McDonald's said: “When this incident was brought to our attention, our customer services team sent a letter of apology to the customer in addition to complimentary food vouchers, however we’d like to further apologise for the delay in responding.

“We recognise that this mistake was unacceptable and we have a number of procedures in place to avoid inaccurate orders.

"Unfortunately in this case, they were not followed. Allergen Booklets are available for customers who require allergen information, which explains that we produce our food in kitchens where allergens are handled by our people, and where equipment and utensils are used for multiple menu items. "While we try to keep things separate, we cannot guarantee any item is allergen free.”