When I first moved to London, I lived in Farringdon and then Marble Arch, and the first couple of years it was awesome to be able to just step outside the door and be in the centre of town (at Marble Arch I literally had two minutes walk to be on Oxford Street, or could cross the road and be in Hyde Park). But the pollution was certainly awful - it's the only place I've lived where your snot would be black at the end of the day. And then I moved to Barnes (South West London - very leafy, very affluent), but when we decided to buy it was too expensive, and we ended up moving to Croydon (zone 5, South). I don't think I'll ever move closer in towards the centre again. If I were to consider moving elsewhere, it'd be either further out, or along the edge of London somewhere along one of the major train lines.
You get the option of working in the centre when it makes sense, it's far more relaxing, greener, far less pollution, and far cheaper.
I can see the appeal of moving somewhere else entirely, but this is a decent compromise for people who want easy access to London but don't want all the downsides of the centre.
A web developer outside of London could expect 40/50K pa where as in London you could earn 600 a day contracting.
That's 2-3 times the money, plus with so many jobs you don't have to worry about becoming trapped.
There's plenty of web dev contracts in the North, but rates might be 400 - 500 a day.
In permanent roles the bump, if any, seems to be around 25%. If you're more junior in PHP the perm roles are similarly salaried in London as outside it (at least going on a friend who complained about this a lot a year or two ago).
A graduate developer at a finance company would earn over 40k...
You certainly can still do extremely well, but the risk is certainly there.
Huh? Manchester, Leeds and Newcastle have plenty of work, you get paid rather less (surprisingly not much less last 5 years - but that's been London rates falling rather than north rising), but keep significantly more in your pocket. The people and beer are nicer in the grim North too.
Aside from during the peak of dot con and y2k contract rate insanity I've avoided London like the plague. It's a great place to visit for a show, but live and work?
I never understood the appeal of earning 25% more, but having 50-70% less in your pocket after housing and travel. It's the only UK city where the pollution is palpable, and constant.