A 19-year-old who was found with a serious head injury at the approach to Rotherhithe Tunnel is in a critical condition in hospital.
The man was found unresponsive on the south side of the River Thames, just before 4.20am.
The Rotherhithe Tunnel remains closed in both directions and police are advising motorists to avoid the area.
No arrests have been made and officers have informed the man’s next-of-kin.
Motorists have reacted angrily to the closure on Twitter.
Social media user @Peterrolland3 wrote: “In awe how well London transports many people, many places; noticeable when it goes wrong! Stuck on jam as Rotherhithe Tunnel closed!”
Anyone with information should call police on 101 or Crimestoppers anonymously on 0800 555 111. See full appeal here.