I don't know how it is in the UK or anywhere else in the world, but in the US we don't seem to require anything of our leaders...
I mean if you need your car repaired you find someone who has the proper training, if you need dental work done you go to a reputable dentist.
But when we need to elect representatives or presidents.... it's enough if we think he's a good guy!
In order to run for any public office one should have some kind of training. Sociology, accounting, economics, ethics, history etc.