The Leyland Olympian was a double-decker bus

Double-decker bus

A double-decker bus is a bus that has two storeys or 'decks'. Global usage of this type of bus is more common in outer touring than in its intra-urban transportion role. Double-decker buses are also commonly found in certain parts of Europe, Asia, and former British colonies and protectorates...

 built by British Leyland/Leyland Bus

Leyland Bus

Leyland Bus was a British bus manufacturer. It emerged from the Rover Group as a management buyout of the bus business...

 in the United Kingdom

United Kingdom

The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...

 from 1980 to 1993. It was the last Leyland bus model in production before the demise of Leyland Bus.
The Olympian was built as a result of the Leyland Titan (B15)

Leyland Titan (B15)

The Leyland Titan was a model of double-decker bus produced by the Leyland Truck & Bus division of British Leyland from 1977 until 1984, almost exclusively for London Transport.-Development:...

, an integral double deck bus which was ordered en masse by London Transport

Greater London Council

The Greater London Council was the top-tier local government administrative body for Greater London from 1965 to 1986. It replaced the earlier London County Council which had covered a much smaller area...

. At the time there was a demand for non-integral vehicles, operators wishing to remain with more established manufacturers.