GM Standard double-decker bus

The GM Standard double-decker bus was a double-decker bus bodywork designed by SELNEC and its successor the Greater [Manchester Passenger Transport Executive] and built on Leyland Atlantean and Daimler Fleetline chassis. No fewer than 1,815 standards were delivered to SELNEC, Greater Manchester Transport and Lancashire United Transport.
A common design is that the bus has its tall lower deck double-curvature windscreen and upper deck double-curvature windscreen with either an arched top or a flat top.