Eight people have been taken to hospital following a serious crash in Edgware involving a minibus, a car and a tree.
London Ambulance Service was called at around 7.30am and sent London’s Air Ambulance, six ambulances, two duty officers, an advanced paramedic and its specialist hazardous environments team to the scene.
Doctors treated eight patients at the scene and they have been taken by ambulance to three north London hospitals, including a major trauma centre.
At 8.15am paramedics were said to be "standing down".
The A410 Spur Road in Stanmore was closed and traffic was reportedly backed up westbound at Canons Corner.
Traffic jams stretched to the A41 Edgware Way junction, on the A41 north up to the Edgwarebury Lane junction and on the A41 southbound lane to Elstree.
The A5 Stone Grove junction at Canons Corner also reported heavy traffic.
Diversions are in place for bus routes 107 and 142.