A 55-year-old man suffered a cardiac arrest at the wheel of his car last night in Greenwich High Road.
The man, who was driving a BMW, collided with a taxi and was taken to Kings College Hospital after the accident just before 9pm.
Temporary road closures were put in place in the area near the Sainsburys.
Buses 177, 180, 199 and 386 were all diverted while police dealt with the crash.
Twitter user Helen S @@helstweets said: "Looks like something bad'd happened on #Greenwich High Road by Sainsburys. Road closed, blue lights, TFL response unit."