A long-serving police constable who was critically injured as he tried to stop a speeding car has died in hospital.
PC Andrew Duncan, a Metropolitan Police traffic officer, was pronounced dead in hospital this morning, following the collision in Sutton, south London, in the early hours of Friday.
The 47-year-old was travelling on foot when he tried to stop a car on Friday when the vehicle struck him.
The married father-of-two suffered severe injuries following the hit-and-run, which involved a black Volkswagen Golf.
Metropolitan Police Commissioner Sir Bernard Hogan-Howe said, "Andy was a hard working and courageous policeman. He served the community as both a police officer and as a Scouting volunteer.
"The night he was injured, he was doing a job that he loved and we all had every right to expect he would return safely to his home and family - tragically that was not the case."
A 25-year-old man arrested on suspicion of causing serious injury while dangerous driving has now been arrested on suspicion of murder.
PC Duncan joined the Metropolitan Police in 1990, working in Battersea, Hammersmith and Fulham before he joined the force's South-West Traffic Unit in 2004.
London Mayor Boris Johnson said, “His death is a tragedy and a reminder of the courage and sacrifice shown daily by the men and women who keep London safe.
“My thoughts and those of every Londoner are with Andrew's wife and children at this time.”