A man in his 60s was airlifted to hospital with chest injuries after a digger flipped over and trapped him on a building site.
It happened shortly after noon yesterday at Windsor Park in Buckingham and the man was airlifted to John Racliffe Hospital in Oxford.
Firefighters helped rescue the man who had suffered chest injuries and police officers made the scene safe.
The ambulance service said the man had ‘life threatening injuries’ but he is now in a stable condition in hospital.
Roger Tappin, who was walking his dog, saw the ‘JCB-type vehicle’ and firefighters battling to save the man.
He said: “It was on a large amount of earth and was rather precariously placed.
“It was upside down and there was lots of police, the air ambulance and firefighters helping.”
A spokesman for the Health and Safety Executive said it was aware of the incident and is talking to the police about it.