It is used in all European countries (I don't know any European country that doesn't use it). I know the long scale under the name "European" and the short scale as "American".
With the exception of people over 70, the UK has pretty uniformly moved to the American system. All of our govt statistics, corporate finances info, day-to-day conversations involving billions refer to "one thousand million"
(And despite Brexit, UK still is a European country!)