Danny Bullen’s first words were "Dame mas papas, por favor" – for those of you who skipped Spanish lessons the phrase means "Give me some more crisps, please".

You may think it’s a strange sentence for a child to speak the first time they are able to talk, but in this case it was a miracle.

Danny spoke for the very first time after undergoing pioneering stem cell therapy to treat his autism which has kept him silent for his first eleven years.

Mum Lee Bullen and her partner Irma Guanche heard their son’s first words last March, just hours after the treatment when they took Danny to the Art and Science Surgicenter in Miami.

After raising 10,000 Euros (£8,600) the family had enough money to travel to America from their home island of Tenerife.

Despite Danny uttering his first sentence he has not manage to string any more words together, it will be a slow progress although his parents are considering travelling back to Miami later this year so he can have follow-up treatment.

The lad needs help carrying out daily tasks, such as going to the toilet and has to abide a gluten and lactose-free diet.

His mother has documented Danny’s condition and how the family has adapted to his needs in a book called ‘Beset’. She said: "Doctors introduced umbilical cord blood stem cells with cells from my son's bone marrow and adipose tissue.

"He had his first treatment in March, and the early signs are very encouraging. He is more alert and has already started to use a few new basic words and greetings.

"Undergoing stem cell therapy over two or three visits usually brings better results, which is why we hope to take Danny to the US at least twice.

"All symptoms related to ASD (Autism spectrum disorder) have completely disappeared in many young patients."

Danny Bullen was diagnosed with autism in 2010 when he was two years old.