The Leyland Titan is a rear-engined double-decker bus manufactured by Leyland between 1977 and 1984, primarily for London Transport. Development The Titan was conceived in 1973 as project B15 and was intended as a replacement for the Bristol VRT, Daimler Fleetline and Leyland Atlantean. Following the success of the single-decker Leyland National, it was decided, from the outset, that the vehicle would be very standardised and of integral construction. This allowed more flexibility in the location of mechanical components and allowed a reduced step-height. The move away from body-on-chassis construction caused concern for the bodybuilders, who had already lost market share to the Leyland National. Talks regarding licensing agreements were held with Alexander and Northern Counties, both major suppliers to their respective local markets, but no agreements were reached. Leyland saw London Transport (LT) as a major market, so the specification was heavily influenced by their preferences. LT was suffering problems with its Daimler/Leyland Fleetline one-person-operated double-deckers and wanted more input into the design. Leyland, too wanted to gain more operator input than had been the case with the Leyland National. Five prototypes (B15.01-B15.05) were constructed between 1975 and 1977, two of which were evaluated in London. Specification The Titan was long, wide and high. The main body structure was aluminium and the body was assembled using Avdel 'Avdelok' rivets similar to the Leyland National. Single and dual-door layouts were offered, with a number of options for the location of the staircase. Mechanically, independent front suspension and a drop-centre rear axle were used, with air suspension and power hydraulic brakes as standard. The prototype engine was a turbocharged version of the Leyland 500 series, although this was changed to Gardner 6LXB for production, as a result of customer preference and concerns over fuel economy and reliability of the 500 series. The Leyland TL11 engine was available for later production versions. The engine was mounted vertically at the rear, with the radiator located separately in a compartment above the engine. This led to an unusual off-centre square rear window. The overall design was advanced for the time and improved on noise and emission requirements by considerable margins. Production The Titan name, previously used for a front-engined double-decker, was revived for production in June 1977. It was intended that Park Royal Vehicles would build the first 100 vehicles, with production then transferring to AEC in Southall. This caused industrial relations problems at