Two pensioners were taken to hospital after two cars collided and one rolled over a central reservation.
The crash between the blue Vauxhall Astra and the grey Renault Megane occurred on the A41, at the junction of Hendon Way and Cricklewood Lane, at 10pm on Tuesday.
One of the vehicles rolled over the central reservation of the carriageway and came to rest on its side.
The two drivers, a 73-year-old man and a 75-year-old man, were both taken to hospital as a precaution.
One of the men was taken to St Mary's Hospital as a priority patient, while the other was taken to the Royal Free as a precaution.
London Fire Brigade, London Ambulance Service and Barnet Police all attended the incident.