A 20-year-old man was arrested in Rotherhithe on Tuesday evening on suspicion of the attempted murder of two police officers near Southwark Tube Station earlier this month.
The man has also been arrested on suspicion of being in possession of a loaded firearm.
A Met spokesman says that the man is in custody at a south London police station.
Blackfriars Road and surrounding streets were sealed off for several hours on Wednesday 5 August after a man fired two shots while two police officers chased him from Hatfields to Blackfriars Road via Isabella Street.
The two police officers escaped serious injury.