OCTB
反黑 (original)
An undercover detective crosses paths with familiar faces in the mafia underworld during the final years of Britain's ruling of Hong Kong.
Starring Jordan Chan, Danny Chan Kwok-kwan, Sam Lee, Ken Wong, Samuel Pang, Rose Chan Ka-Wun, Philip Chan Yan-Kin, Justin Cheung, Michael Chan, Philippe Joly
It's a action & adventure and crime show, and has a rating of 7.1 out of 10 from Imdb which is usually fine for this kind of show.
Watch it here
Not found streaming from United Kingdom.