Fare-paying passengers climbed aboard the first of London's new "Boris buses" today amid protests that the vehicles were a waste of money.
Following a pledge by London Mayor Boris Johnson, hop-on, hop-off red double-decker buses returned to regular services in the capital.
The first of the buses set off from Hackney in east London on route 38 which ends at Victoria station.
But following the new driver-and-conductor vehicle was a "protest" bus covered in slogans attacking the rise in public transport fares in London.
According to several reports, the Boris bus briefly broke down, with the protest bus sailing past.
Additionally, a software glitch meant the bus had to be run with the rear platform shut, the BBC reported.
Despite these mishaps, Mr Johnson today described the new bus, built by Northern Ireland company Wrightbus, as a "stunning piece of automotive architecture" which represented the very best in British design, engineering and manufacture".
Scroll down for a slideshow of pictures from today's launch
But Manuel Cortes, leader of the TSSA transport union, described the new bus as a "vanity project," while David Lammy, Labour MP for Tottenham, wrote to Mr Johnson, asking how the Mayor could "justify the extraordinary cost and diversion of resources of procuring the 'new bus', which has come in at a price of £1.4 million per bus".
The last of the popular open-platform Routemasters was withdrawn from regular service in December 2005, although some still run on tourist routes in addition to the closed-door, driver-only regular buses.
Mr Johnson promised a return for a new "green" successor to the Routemaster as well as vowing to get rid of the ultra-long bendy buses, which have now all been withdrawn.
The first of the new buses is being operated by transport company Arriva. In total, eight of the new buses will enter passenger service in the first half of this year.
London-based designers Heatherwick Studio have provided the exterior and interior design of the new buses.