Federalise the British Empire (at least the Dominions) and butterfly away WW1 (& thus WW2), then have them wage a slow and methodical war of conquest in the far parts of the world.
That should produce the largest possible "British" culture.
Yeah, one of the few cases we get something earlier than the yanks. :D
No doubt you could order it from down under earlier if you wanted, I often do the opposite when I can't be bothered waiting months for a local release.
Cold war goes hot, America defeats the Soviet Union, suffering minimal loses on their own soil. In the aftermath they deploy hundreds of thousands of troops to a decimated Europe to prevent it from totally collapsing. As a result of this major deployment a significant portion of the population...
Disclaimer: This is not intended to be a racist remark, but is instead intended as a possible, though quite implausible, way for this POD to occur.
Now that we have that out of the way.
All/most African-American former slaves become criminals.