the Slavs have always been host to the enemies of Britain.  E.G., Polish-Lithuanian Commonwealth accepted over a hundred thousand Scottish Catholic refugees from Protestant Britain (Scottish Mercenaries, as a result, were quite prominent in the Commonwealth Army and eventually assimilated into local communities in Belarus, Lithuania, Poland and Ukraine).

In terms of foreign policy, Britain was always a chief ally of the Ottoman Empire and the Ottoman Empire was virtually the biggest enemy of the Slavs.  The Ottoman Empire was meant to fail and collapse centuries before 1918 but was largely propped up by the British and French, as a result, the Balkan states didn't really gain independence until the 1880s.

Both Britain and France were also major allies to the Hapsburg Empire, who were also a major oppressor of Hungarians and Slavs.