A road was closed in Stanmore after a car collided with a woman outside a supermarket.
The Broadway closed after a woman in her 30s was hit by a blue Honda Accord at 12.52pm yesterday outside Sainsbury's, in The Broadway, Stanmore.
The woman suffered serious injuries to her head, pelvis and back and had to be taken to the Royal Free Hospital, in Hampstead, for treatment.
An ambulance and fast response unit went to the scene.
Traffic is being diverted from the area and an investigation has been launched by the police into the cause of the smash.