Two people were taken to hospital with what are believed to be minor injuries after the collision between a white Ford Transit and a silver Volkswagen Eos.
The crash happened at 8.02am on Chittleburn Hill at Brixton.
Almost an hour later police said the road was still blocked.
The ambulance service called the fire brigade as a precaution. They took the driver of the Transit to hospital, and at 8.54am the other driver was on a stretcher and on the way to hospital.
A police spokesman said the airbags of both vehicles were inflated in the crash.