The TD

Leyland Tiger single-decker
After the war, the single-deck fleet was in poor shape, with many early buses overdue for replacement.  However, with attention understandably focussed on the need for new double-deckers, the stop-gap decision was made to purchase for the Central Area a number of AEC Regal IIIs (50 buses classified 14T12) and Leyland Tigers (131 in total, classified TD). 
These buses were standard products and did not reflect the advances made by London Transport before the war.   The Regals were delivered in 1946, followed by the first 31 Leylands, all with bodies by Weymann.  The second batch of 100 TDs followed in 1948 with bodies by Mann Egerton, to a design very similar to those provided by the same company for the Country Area AEC 15T13s.  Unlike these last of the T class which had RT-type engines and transmission, however, the later TDs still had crash gearboxes.
The TDs were used on a number of routes around London, including the 236 and 210, but with the reduction in bus traffic, they became surplus to requirements and last ran in service in 1962 at Kingston and (last of all) Edgware.