[richrichie]

I hope you have decent source of secondary income or your family is reasonably well off.

A math PhD might take 6-7 years to complete and I hope that, at the end of it all, you won’t have to come to London to look for C++ or Ocaml jobs at hedge funds or banks.

[xanderlewis]

I'm in the UK. It takes nominally three years here; usually three and a half. I also have full funding.

...this is the discouraging negativity I'm talking about. I do, respectfully, wonder what your agenda is.

[richrichie]

Because i have worked with many math phds who lost their youth to something that they could not make a living on (research positions at universities are few and the competition is intense) and were writing C++ implementations of derivatives pricing models for a (comfortable) living.

I am not trying to discourage you, just a different perspective.