A minicab driver was sent on a back-and-forth journey through south London before being ambushed by a gang of thugs assembled by his passenger.
Police said the driver and the passenger became embroiled in a series of arguments during the bizarre journey on December 12.
Having been driven through south-east London for almost an hour, the customer asked to be returned to the original pick-up point of Invermore Place, close to the garages near Walmer Terrace.
On the way there the passenger made a call, and the driver heard him asked the person on the other end of the line to meet him at the garages.
As the cab arrived at its destination the driver noticed five men waiting in the area.
He was then dragged from his silver Skoda and brutally assaulted, leaving him with head and hand injuries.
The attackers are then said to have made off with £30 they stole from his car.
Graphic footage of the assault was later uploaded to social media after the incident was filmed on a mobile phone.
Police today issued an appeal to trace a man in his 20s in connection with the incident.
The suspect is a slim black man, with a beard, who spoke with an African accent, police said.
Detective Constable Danny Banks, from Greenwich CID, said: "We want to urgently speak with anyone who saw this vicious robbery and assault, or who is aware of this incident and can assist with our ongoing investigation."
Anyone with information should contact police via 101 or Crimestoppers anonymously on 0800 555 111. Calls to Crimestoppers are free.