Two women and two men were injured in a three-vehicle collision on the A40 this morning.
Two cars and a van collided near the Polish War Memorial turn off in South Ruislip.
London Fire Brigade (LFB) was the first emergency service on the scene.
"We were called at 11.02am to reports of a car crash," confirmed a LFB spokesman. "Two women were trapped in their cars due to their injuries. The situation was under control by midday."
London Ambulance Service were called at 11.11am and arrived soon after.
Two patients were taken to Hillingdon Hospital and the other two to Ealing Hospital.
Their injuries are not thought to be serious.