As someone who once lived in London for about 10 years: Go anywhere else. Yes, fewer opportunities, but not NO opportunities. And what you may lose in salary,

As someone who once lived in London for about 10 years: Go anywhere else. Yes, fewer opportunities, but not NO opportunities. And what you may lose in salary, you will win doubly and triply in quality of life, lower living costs, lower transport costs, etc... What truly matters is the lack of stress from the truly adversarial environment that London's commute represents. (Though, having been to HK also, I guess London is actually not too different, in terms of what stereotypical, huge cities are like.)