A boy has been reunited with the professor who saved his life - 12 years later.

Thomas Hay met with a King’s College Hospital professor, Kypros Nicolaides, more than a decade after a ground-breaking pre-natal procedure increased his slim survival chances dramatically.

Back in 2011, Thomas was diagnosed at 20 weeks with Congenital Diaphragmatic Hernia (CDH) during a routine pregnancy scan.

Recalling the moment, his mother Lucy Hay said: "It was absolutely devastating.

"We were told our baby had a hole in his diaphragm, allowing his abdominal organs to push through into the chest cavity and crush his lungs.

"At the time, we were told he had a 50% chance of survival."

News Shopper: Before his in-utero surgery, Thomas' chances of survival were below 2 per centBefore his in-utero surgery, Thomas' chances of survival were below 2 per cent (Image: King's College Hospital)

Ms Hay, upon researching, came across the experimental in-utero surgery led by Professor Nicholaides, Professor of Fetal Medicine at King’s College Hospital.

At an appointment with Professor Nicolaides, Ms Hay found out that Thomas' condition worsened, reducing his survival chances to below 2%.

Ms Hay remembered: "An hour later, after a lot of encouragement from my husband, I was on the operating table."

News Shopper: Thomas was born at 37 weeks in August 2011Thomas was born at 37 weeks in August 2011 (Image: King's College Hospital)

The procedure involved inserting a miniature latex balloon through Lucy's uterus into Thomas’ windpipe, aiming to encourage lung development.

Lucy said: "My husband and I watched on the monitor as Professor Nicholaides inserted a camera into my womb and we saw him carefully guide it through our baby’s mouth and down into his windpipe."

Following the successful completion of the procedure, Thomas' lungs showed remarkable growth.

Thomas was born at 37 weeks in August 2011.

Today, Thomas is a healthy 12-year-old and, apart from suffering with asthma, leads a normal life.

News Shopper: Thomas said it was amazing to finally meet the man who saved his lifeThomas said it was amazing to finally meet the man who saved his life (Image: King's College Hospital)

His mother said: "No words or actions would ever be sufficient or appropriate to express the immense feeling of gratitude we have for Professor Nicholaides."

Thomas added: "It was amazing to finally meet Professor Nicolaides.

"After hearing so much about him and what he did for me before I was born, I was very excited and grateful to be meeting him."

It was a mutual feeling.

Professor Nicolaides said: "It was a great pleasure meeting Thomas.

"He's doing brilliantly and it makes a big difference to me when I see such excellent results of our fetal interventions."