I'm an LSE grad, and would argue that it is by no means the "no brainer" that karalime suggests.
It depends how much he is motivated by course, and how much by location. If the latter and he has a desire for dreaming spires, then you have your answer.
If not, and he has a genuine interest in economics and economic geography, then really consider LSE. It is surprising how many of my peers later forget that they studied geography at all and a decade after graduating would airily say "when I studied economics at the LSE". LSE economics is very employable, and if a joint degree, he ought to be able to bend his degree a long way towards economics should he want.
One thing to watch is that LSE courses often have a lot of maths. Obviously if he likes maths, that is perfect, and there again would probably be quite a lot of scope to access high quality and related stats and other quantitative courses which certain employers would really like.
DS is reading economics at LSE and is really happy. He is very interested in his subject, and being in the centre of a world city means that all sorts of interesting academics, speakers, and researchers pass through. The student body is also truly international and some of his peers are super bright and interesting. Because economics is such a large degree, he has been able to flex his to really focus on the maths side and avoid writing essays whilst friends have focused on economic history, philosophy or more vocational accounting and finance.
But he is not someone who felt the need for dreaming spires, and so he does not feel his misses out on University experience, but rather that he is getting the sort of University experience he wants.
He is applying to both Oxford and LSE for Masters. It will be interesting should he offered places at both. I would like to see him leave London, but suspect he will be reluctant to leave the LSE.
There will be all sorts of posts about how expensive London is etc. DS spends remarkable little. There are lots of things in London that are free, the transport is great, and the LSE campus is pretty active.