As a teacher, Ada began making plans to leave when Hong Kong's government instructed schools to adopt a pro-China curriculum.
Dubbed as a mix of high-energy caper and moving bromance tale, the movie boasts a stellar cast starring Choi Min-sik as Prisoner 203, a terminally ill convict who wants to break out of jail to his daughter for the last time.
It is not clear how many of them will make the move to Britain.