Lennox's parents have maintained a vigil at his bedside

Lennox Nicholson, who is five months old and from Guisborough, in Teesside, developed jaundice and chronic liver problems soon after his birth.

As his condition worsened parents Simon Nicholson, 21, and Amy Robinson, 20, launched an appeal for a donor, and a new organ was found on Tuesday morning.

Lennox will spend at least three weeks in Leeds St James University Hospital.

Lennox's family faced an anxious wait for news of a potential donor, aware that the boy's condition was worsening.

We have never had a death in an elective paediatric liver transplant patient, so we have 100% survival in our routine cases. Steve Pollard

But in the early hours of Tuesday, a donor was found and the operation to transplant half of an adult liver took place later that morning.

Explaining the operation, Steve Pollard, a transplant surgeon at St James Hospital in Leeds, said: "It's very complex and is only possible in three or four hospitals in the UK.

"It requires a lot of infrastructure and surgical skill to divide a liver into two portions. The majority or babies don't receive baby livers because there are very few baby donors, so a child waiting for one the right size would probably die while waiting.

"The new liver will grow with the child and will shrink if too big and the child will grow up and have normal life expectancy."

He said livers were more immune to rejection than kidneys and hearts, and long-term rejection was uncommon.