I'm not sure how the relative geographical size of the Bay Area is relevant here. In terms of programming jobs, the Bay Area is a very significant part of the U

I'm not sure how the relative geographical size of the Bay Area is relevant here. In terms of programming jobs, the Bay Area is a very significant part of the US. In any case, this and other polls indicate that programmer salaries in London are also lower than in many other large American metropolitan areas, not only SV. I did a quick search on Indeed for software engineer salaries in several American cities (NYC, Seattle, Chicago, Boston, Houston, Austin, Portland, Miami, whatever came to my mind) and in all of them the average salary is over U$85k. In fact I also searched for junior software engineer and in all of them it's at least U$60k, still within the £40~45k range which is the mode of the poll (and presumably filled with mostly non-junior developers). If you look at average programming salaries in Tokyo or Paris you'll see a similar thing. The interesting question is not why London salaries are "low", but how come American salaries are so high.