IIRC it was the first US Number One charting song from a British act. It wouldn’t be the last.
Vera Lynn was the first Britisher to top the actual charts in this country with Auf Wiedersehen (Goodbye) in 1952. But much as I love Vera Lynn, this is a knockoff, and I like the original better.
Auf Wiedersehen--Rudi Schuricke (1950)