Boris Johnson has unveiled the final design for London's new-look double-decker buse, the Guardian reports. 
The vehicles - to be introduced in 2012 - were a key part of Johnson's election manifesto and will feature two doors as well as an open platform allowing passengers to hop on and off. According to the mayor's office they will have two staircases and be made of lightweight materials, making them 15 per cent more fuel-efficient than existing hybrid buses and 40 per cent more efficient than conventional diesel double-deckers.
The buses are to be made by Wrightbus, based in Northern Ireland.
Johnson said: "This iconic new part of our transport system is not only beautiful but also has a green heart beating beneath its stylish, swooshing exterior. It will cut emissions and give Londoners a bus they can be proud of, complete with cutting-edge design and the freedom of an open platform."
The Routemaster was withdrawn from regular service in December 2005 by then mayor Ken Livingstone. Johnson took office in 2008 promising to bring back a "greener" version of the bus, which was first introduced in London in the mid-1950s.
"I expect to eventually have hundreds of these on London's roads, and for cities around the globe to be beside themselves with envy for our stunning red emblem of 21st-century London," Johnson said.