It could be the top end of Lake Ullswater, Cumbria.
The lake is on the left hand side of the road when you are travelling towards Glenridding and Patterdale.
If so the mountain on the left of the picture is part of Martindale deer-forest.
I don't know, but if I were to take an educated guess, I'd say it's in Scotland. If I had to be more specific, I'd say it's on one of the islands off the west coast of Scotland. If it needed narrowed down more, I'd have to take a stab in the dark at the Isle of Lewis, or perhaps Arran. Or could be any of them. Or none. Am I warm?