The parents of a three-year-old girl who underwent a life-saving medical world first said today their gratitude to hospital staff "can't be expressed".

Abigail Hall, from Lenzie, near Glasgow, was born with only one working heart chamber.

On December 4 she became the first child with such a condition to successfully have a Berlin Heart - a hydraulic pump - fitted, which kept her alive long enough for her to have a heart transplant.

Abigail's father Stephen, 40, speaking at the Freeman Hospital in Newcastle where the operation was carried out, said: "Our gratitude can't be expressed."

Dr Richard Kirk, a consultant paediatric cardiologist at the Freeman Hospital, said: "A Berlin Heart sucks blood out of the heart, pumps it up to full pressure and pushes it into the body's arteries."

The device sits outside the body and is controlled by a computer.

Dr Kirk said Abigail was "extremely lucky" - not only because the Berlin Heart was successfully fitted, but also because a heart became available for a transplant soon afterwards, on December 10.

Abigail's mother Gillian, 35, said: "We just had to have faith - faith in the team here that they could perform miracles, and they did."