With a POD post-Alfred the Great, have a mass immigration of the inhabitants of the British Isles take place to Scandinavia, to the point where Scandinavia is definitely influenced by British culture in its language, genetic makeup, society, etc.
Extra points the later this takes place, and extra points if you make the majority of today's Scandinavian population the descendants of immigrants from the British Isles.
Extra points the later this takes place, and extra points if you make the majority of today's Scandinavian population the descendants of immigrants from the British Isles.