A police officer has suffered potentially life-changing injuries and three others have been injured in a collision in Southwark, the Metropolitan Police said.
A man has been arrested on suspicion of attempted murder following the incident.
A police statement said: "A police vehicle was involved in a collision with another car shortly before 1.30pm on Tuesday, October 20 in Draycott Close near to the junction with Edmund Street, SE5.
"The driver of the police vehicle remains in hospital with potentially life changing injuries. Another officer also remains in hospital with injuries that are not believed life-threatening or life-changing.
"Two other officers have been discharged with minor injuries. Another officer sustained minor injuries in the arrest.
"The driver of the other vehicle- a man aged in his 20s - was taken to hospital. His injuries are not believed to be life-threatening.
"He has been arrested on suspicion of attempted murder."
Photos from the scene show two vehicles in the middle of the street, just beyond a speed bump, with one heavily damaged.
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