It's hard to convey how bad the housing situation is in London to people that have not lived there. Starting income is much lower than Silicon Valley (a very, very good pay for your first job is around ~40,000 pounds/year), housing costs are insanely high, and public transport is crazy expensive.

It's possible to live there as a young person with multiple room-mates, living far away from the city center, but as you get older and want things like privacy or, god forbid, enough space to live with a family, it becomes completely unaffordable. The city center has gotten so expensive that even bankers and russian millionaires cannot live there - it basically exists now to cater to Middle Eastern billionaires: http://www.bloomberg.com/news/articles/2014-12-17/russians-q...

London is an awesome city, I'm glad I lived there during my undergrad, but there's no way I could go back there as a 30 year old. The city will constantly be appealing to the young, who don't mind squeezing with three other people into a small apartment in zone 4, or the extremely rich, but for everyone else, move far, far away and you'll be a lot happier, even with everything (and, it's really a lot) that London has to offer.