The Cut will be closed to through motor traffic for three weeks from Monday 18 May due to works by Southern Gas Networks and construction of the new cycle superhighway on Blackfriars Road.
The roadworks will take place at the eastern end of The Cut near Southwark Underground Station.
Transport for London says that access for cyclists will be maintained during the roadworks.
During the closure, northbound traffic on Blackfriars Road will also be banned from turning right into Union Street.
Motor traffic heading west towards Waterloo from Union Street will be diverted via Blackfriars Road and Webber Street.
Other through traffic that would normally use The Cut will be diverted via Stamford Street or Waterloo Road.
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