CCTV released by Westminster Council shows the moment an innocent shopper is targeted by a fraudster on Oxford Street.
A gang member can be seen bending down to pick up a ring - but in this case the target gets away without falling for it, after a warning from a council binman.
More top news
Six people were injured after they were hit with the substance during an "altercation" between two groups at a shopping in east London.
Save Your Uber in London was set up after it was announced the firm would not have its licence renewed when it expires next week.
Survivors are still traumatised, homeless and want answers.