A schoolboy was rushed to hospital after he was hit by a car on a busy road in Northolt.
Emergency services raced to the scene after the 14-year-old was struck by the vehicle in Church Road shortly after 3.30pm on Tuesday.
Witnesses described an air ambulance landing nearby as the child was treated by paramedics at the scene.
The boy – who reportedly attends a nearby school – is believed to have been crossing at the traffic lights outside Northolt Library when he was hit.
A Met Police spokesman said: “We were called at 3.48pm to Church Road to reports a collision between a car and a pedestrian.
“The pedestrian, 14-year-old boy, was taken to hospital with head and arm injuries."
The boy's injuries are described as serious but not life threatening, police said.
Road closures were put in place and motorists were warned to avoid the area.