The first of a new-style hop-on, hop-off bus that will go into passenger service next year has been driven off the production line by London Mayor Boris Johnson.
The symbolic ceremony took place in Ballymena, Northern Ireland, at the factory of the Wrightbus company.
Hop-on, hop-off buses have not run as part of the scheduled service in London since the last driver-and-conductor Routemaster was withdrawn in 2005.
The first eight of the new double-decker buses, which have three entrances including a Routemaster-style open platform, will enter passenger service in the first half of 2012.
The first will be operated by the Arriva transport company and will run on "a busy central London route".
Mr Johnson said: "This fantastic machine is chock-full with the latest technology and London buses will be world leaders once again when the first eight buses take to our roads early next year.
"They are just an advance party for what I envisage will eventually be a legion of their type. Our new bus is an improvement on standard double decks in every respect and has been designed with this city and its wonderful population in mind.
"It showcases the very best of British manufacturing and design and simply oozes with quality."
The mayor said the bus would be on the streets of London by January. "It looks fantastic, it feels fantastic," he said. "I think the features are brilliant."
He also dismissed criticism of the cost of the project, rejecting those who claimed each of the initial eight buses had effectively cost £1.4 million, and also pointed to exports of the bus as a revenue stream, asserting: "We're going to be able to flog this thing around the world."