I grew up reading Enid Blyton's and James herriot's books. And watched quite many british tv series, like Shoestrings, All creatures great and small (my favorite), tinker tailor soldier spy, .. what else ... the Beatles said that "you get a tan from standing in an English rain"
Anyway that left me with one particular picture I see each time I hear about UK ... I know it's not accurate, but here's the picture I see: cloudy all the time