A plucky man jumped into the canal at Westbourne Green in a desperate bid to escape two robbers.
The 24-year-old was walking home after work along the Grand Union Canal towpath near Alfred Road, when two men came up to him, one on a bike.
Believing they were about to rob him, he plunged into the canal and swam to the other side.
The man turned around and saw the yobs hurl a bike into the canal behind him.
The thugs were black, around 17 years old and wearing hooded tops.
Anyone with information about the crime, which happened last Tuesday at around 7.30pm, should call Westminster police on 020 7321 6510 or Crimestoppers anonymously on 0800 555 111.