Are there any major differences between American and British SF? If so, what are they and what is the reason for them?

In the latest issue of Locus Magazine (Dec 2007), reviewer Graham Sleight says a couple of interesting things about the differences between American and British SF:

One of the interesting tensions in [Greg] Bear’s work is between the American and British strains of SF. Broadly (and here I’m borrowing from Brian Stableford’s The Scientific Romance in Britain (1985)), British SF derives from the scientific romance tradition of Wells and Stapledon, in which protagonists observe (often in wonder) but do not change the world. In American SF, they do, and the future is something to be worked on, conquered, perhaps owned.

I definitely have a greater affinity for the American strain. The British strain seems to lend itself well to cynical or satirical dystopian stories; the American strain more likely to be hopeful and productive of a libertarian future. Ayn Rand’s Anthem is a dystopian novella with a distinctly American ending.

In a sense, [Alastair] Reynolds’s book [Revelation Space (2000)] should be seen here as emblematic of what other British writers have been doing recently: taking the props of American SF and putting a distinctive dark perspective on them. …. The end of the book opens up the sort of cosmological perspectives one associates with Stapledon (or Baxter), but does so in a story where individual actions make a difference.

I’m not a huge fan of the cosmological perspective stories in which individual actions don’t make much difference. They’re dreadfully pessimistic and dark. And while a cosmological perspective, used in moderation, can offer us a wider perspective on the present, it is a mistake to think that this perspective is primary for telling/showing us what is really important and valuable. I think some SF authors make this mistake. Is it a distinctively British one?