Police are investigating a road collision involving Sir Keir Starmer, which saw a cyclist taken to hospital.
The Labour leader is understood to have been driving in the Kentish Town area of north London when the incident happened around midday on Sunday.
A spokesman for Sir Keir said he stayed at the scene until an ambulance arrived and reported the incident at a police station later that day.
The Met Police said the driver was not arrested nor interviewed under caution.
They added that the male cyclist suffered a minor injury to his arm and was taken to hospital by ambulance "as a precaution".
Sir Keir, a former director of public prosecutions, is not believed to have been injured.
A spokesman for the Labour leader said: "Keir was involved in a minor road traffic accident on Sunday.
"He spoke to a British Transport Police officer who attended the scene and swapped details with the officer and the other individual involved."
"Since the incident, Keir has also been in touch with the other individual involved," he added.
The Met Police said it was alerted by the London Ambulance Service at about 12:20 GMT to a report of a collision between a cyclist and a car in Grafton Road.
"The driver of the car had stopped at the scene and exchanged details with the cyclist but had left before officers arrived," the force said in a statement.
Officers from the Roads and Transport Policing Command were investigating the collision, the statement added.