Smoking is banned in all ­public indoor areas including malls and public transport facilities, and some outdoor areas such as parks. Offenders face a fixed fine of HK$1,500.

Kuan recalled: “I told him not to run and said: ‘You have committed an offence. Stand still!’”

He is among a group of 20 ­former policemen, most in their 50s, spending their retirement cracking down on smoking offenders. [...]