IBARW Day VI: further links
The Black GIs in UK during the Second World War, and their offspring. The story tends to be told as oh how very much more tolerant and liberal the Brits were than those Yanks, but this account shows how very much more complicated a tale it is and that attitudes weren't that much more accepting. I'm not persuaded that British policy-makers were simply responding to official US racism in becoming less tolerant, either.
I might allude here to Susan Williams' book Colour Bar, about the response of the British government to the marriage between Seretse Khama of Bechuanaland (subsequently Botswana, of which he became first president) and Ruth Williams: brief account here:
The reason for this hostility to their marriage was simply the difference in the colour of their skin: Seretse was black and Ruth was white. The British were under heavy pressure from apartheid South Africa and Southern Rhodesia, which did not like the idea of a prominent mixed marriage on the other side of their borders. But in any case, the marriage met with little approval in the corridors of power in London.
This is a story from which the British government emerges very badly - it lied to the House of Commons, to the people of Botswana, and to the British public. But it is a story from which Seretse and Ruth, and their nation, emerge with honour.
Earlier than one might have imagined (and with a broad anti-racist remit) The League of Coloured Peoples f. 1931; more about it on the excellent Migration Histories website.