The RT
AEC Regent III - London's classic double-decker


Leyland Titan PD2 double-decker
Designed before the second world war, the first RT was delivered in 1939, and another 150 followed before the war put a stop to production.  After the war, the first post-war bus was delivered to Leyton Garage in 1947 for the replacement of open-staircase LT class buses, and by the end of 1947, route 38A was partly converted to RTs.  The early buses were delivered with the distinctive roof route-number box, but this was discontinued after the first few batches.
As part of its requirement to use more than one supplier, London Transport also purchased over 2,100 Leyland Titans.  The RTL class were modified to carry bodies identical to the RT, whilst the 500 members of the RTW class were London's first eight-feet wide double-deckers, in later years proving useful in training Routemaster drivers.
Deliveries of the RT family continued until 1954, when, numbering nearly 7,000, they comprised the largest standardised bus fleet in the world.  Like the single-deck RF, they were operated in red, green and Green Line liveries.
For many, the RT family represents the London bus and it remained in service for 40 years until 1979.  Its successor, the Routemaster has beaten even this.