There are several 'DRT' bus schemes running in the country - that's where you can order a bus using an App on demand, rather than having it scheduled to a timetable. The nice people down at Go Coaches down in Sevenoaks invited me down for the day to try out their service ... and ride on some buses, completely on demand!
Go Coach Sevenoaks Buses: http://www.go-coach.co.uk/