A family in the UK have shared the “miraculous” story of how their little boy Noah is defying the odds after being born with just two per cent of a brain.

Throughout her pregnancy in 2012, Shelley Wall and her husband Rob Wall were told five times to terminate their pregnancy.

Appearing on Good Morning Britain this week with their son Noah, now six, the couple explained how they were told by doctors that their unborn child had “half a brain” and even “no brain” at all.

He had been diagnosed with a condition known as hydrocephalus, where fluid builds up in the brain, or in this case Noah's skull, and the prognosis was bleak, with doctors telling the parents he would not survive.

But the couple refused to terminate and welcomed Noah via caesarean on 11 November.

When asked why they didn't consider termination, Rob suggested it was because they were aged in their 40s and already had the experience of raising two girls.

"I think possibly if younger people were offered that choice, they may have felt pressured into taking it," he said.

"Because we’re older parents, we know our own minds and we’re positive people. We wanted to give Noah the chance of life."

Right from the moment they heard his "amazing", powerful cry, they knew they'd made the right decision.

From there, little Noah continued to defy medical experts' expectations.

The Walls were told that Noah wouldn't be able to talk, see, eat or hear.

But Noah, who was also diagnosed with Spina bifida, can do all those things and is continuing to grow and learn, recently adding surfing to his list of skills.

His parents hope that one day Noah, who was paralysed from the waist down but is learning to move his legs, will be able to walk thanks to a specialist therapy in Australia.

Noah's dad explained to the breakfast show hosts that the treatment is called "neurophysics" and employs both physiotherapy and cognitive exercises.

Rob explained that although Noah is too young to take part, they managed to convince them to give Noah an assessment so he can undergo the treatment when he's ready.

"It’s all to do with the brain’s ability to heal or correct the body’s nervous system."