A six-car collision closed the A316 in Twickenham on Saturday morning.
Police were called to the Hospital Bridge Road roundabout at about 9.15am following reports of a collision.
The driver of one of the cars had to be cut free by firefighters from Feltham and Wimbledon fire stations.
She was taken to hospital and is believed to be in a life-threatening condition.
A Met Police spokeswoman confirmed two further people were taken to hospital with serious injuries following the crash.
A London Ambulance spokesman said: “We were called just before 9.15am on Saturday following reports of a collision involving several vehicles.
“We sent a single response car, two ambulance crews and a duty officer to the scene.
“One patient, a 21-year-old man, was taken as a priority to Charing Cross.
“A second patient was sent to West Middlesex Hospital.”
No arrests have been made.
- Did you see the crash? Call the newsroom on 020 8744 4272.
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