The whole of Scotland used to be criss crossed by Advisory Routes whereby the pilot followed a specific route marked by navaids which was 'deemed' to exist 5nm either side of its centreline but which was not, until the 'classifications' of airspace were introduced in about 2004 actual controlled airspace ie anyone could operate in it without communicating with the 'controlling' authority and an Air Traffic Advisory Service was available to participating aircraft. From then until recently it was Class F airspace but I think it's now been re-classified Class E.