Lincolnshire police have released the name of the police support officer who died in an accident involving an ambulance and a marked car.
Walter Holmes, 59, known to family and friends as Tony, was injured on the B1200 at Saltfleetby St Peter near Louth on Monday.
The police car ended up in a dyke and Mr Holmes was trapped in the water for half an hour.
He died in Grimsby Hospital in the early hours of Tuesday morning.
Two ambulance drivers received minor injuries and were released from hospital soon after the incident.
There were no patients in the ambulance at the time.
Lincolnshire Ambulance service has launched an inquiry.