Pc Bradley Corke, 27, died on Saturday after the incident in Kent on Thursday.
An officer has died and his colleague is in critical condition following a car crash while responding to an “immediate call”, police have said.
A member of the public who was in the second vehicle is receiving treatment for serious injuries, according to Kent Police.
The incident was near Farningham on Thursday and “popular colleague” Pc Bradley Corke, 27, died on Saturday.
A marked Ford Focus police car and Volkswagen Scirocco collided on the westbound A20 London Road at the junction with Button Street at about 7.45pm.
The officers had been travelling to an emergency incident in nearby Swanley, the Kent Police Federation said.
Kent Police said in a statement on Sunday: “Bradley selflessly gave up his life while trying to save the lives of others who were in danger.
“His bravery, dedication, and passion for helping others will not be forgotten.”
The force said it is “supporting his family and colleagues, who are devastated”.
Tonbridge-based Pc Corke joined the force in May 2022 and served the towns of west Kent.
Neil Mennie, chairman of Kent Police Federation, said in a statement: “We are all absolutely heartbroken to learn of this news.
“Bradley was a popular colleague who will be much missed and we will be doing all we can to support his family and close colleagues at this time.
“Policing is a family and words cannot describe the pain we are all feeling, and how this news will affect us in the days, weeks and months ahead.
“This sad incident serves as a horrific example of the risks police officers face and how police officers can sadly make the ultimate sacrifice as they strive to keep the public safe.”
Police are appealing for information and asked witnesses and those with dashcam footage to contact the serious collision investigation unit on 01622 798538 quoting EW/AL/025/26.
