[abritinthebay]

Partly that's due to competition for the small pool in SF being larger. There's a lot of people looking for fewer jobs in London (tech especially). In SF - reverse.

[nemo44x]

I think it goes for other industries too. My wife who works in finance and accounting makes quite a bit more in NYC than she did in London, even for similar roles in similar industries.

But you may have a point in that London being the only game in town has a lot of competition among the workforce. Also, I believe it costs much more to employ someone there and there are many more protection for employees. For instance, it is very difficult to fire someone in the UK and it is not that way in the USA.

[abritinthebay]

That's also true, though I doubt it makes that much of a difference to salaries.

Simply put: I could quit my job today and have a month of interviews lined up in a few days in SF. In London? Not enough companies to sustain that.

That leads to companies competing for talent on wages.

London is great but it never really got a tech boom like SF did.