Dr Bishop said: "Although it will be some years before we are able to build actual human lungs for transplantation, this is a major step towards deriving cells that could be used to repair damaged lungs."

Professor Stephen Spiro, professor of respiratory medicine at University College London Hospitals NHS Foundation Trust and spokesman for the British Lung Foundation, said: "This is very exciting, but there is a lot more work to do."

He said there were many other cell types that make up the lung that would be needed to make new organs.

But he said the cells that the Imperial team had made were crucial for lung function.

"It's always been a huge challenge to replace the damaged air sacks in ARDS. Maybe these cells will be the beginning of something," he said.