Not primarily double-decker, but this one was for some time. There used to be the 30 that ran from Farnborough to Basingstoke, which included about five double-runs AFAIK: one to serve RAF Odiham, one to loop Zebon Copse and Church Crookham, one to serve Fleet Rail Station, one to loop at Minley Estate and one to serve Farnborough Rail Station, not helped with an interworking route 31 beyond to Frimley Park Hospital (had we left the EU sooner that section may as well be part of the 30!).
It was introduced by Stagecoach during the time they held the Fleet Buzz subsidiary in 2013 to replace their route 200/100/10 (renumbered over time in that order), which too ran from Basingstoke albeit to Camberley a few miles north, in unison with algamating Fleet Buzz's existing routes out of Farnborough and Fleet. During this course of time, alongside the step-entrance Varios and low-floor single-decker ex-London castaways, a few of their Leyland/Volvo Olympians began running on this route, mainly acting as backup. To translate Stagecoach English to Standard English, this meant it was regular thanks to the Buzz vehicles unable to start up in the morning.
It was withdrawn in 2015 - partly because of Hampshire County Council budget cuts; partly because South West Trains had a quicker, more frequent service from Farnborough to Basingstoke; and partly because the staff disliked its huge length - which was also when Fleet Buzz merged into the main body of Stagecoach South, and to this present day the 13 (Basingstoke - Haslemere) and 10 (Farnborough - Church Crookham) replace about two thirds of the 30 but never shall the twain meet.