Boris Johnson has been accused by senior London politicians of "wasting" over £400,000 of public money on designing London's new Routemaster buses.
The London Mayor was also accused of "breaking his promise" that the cost of the newly designed bus, which was swiftly exposed for having poor ventilation, would be borne by private business.
The London Mayor's latest model of buses, named the "New Bus For London", started service on February 2012 on select routes. The new double-decker buses were built by Northern Irish coachbuilders Wrightbus and designed by London design studio Heatherwick, who also designed the Olympic Cauldron used for the London 2012 Olympic Games.
Transport for London has admitted that Heatherwick were paid £428,000 for their work on the new London bus, after a Freedom of Information Request from the Huffington Post UK, as part of the wider £11.4 million project cost.
The buses' introduction sparked controversy after malfunctioning ventilation and a lack of openable windows meant passengers suffered temperatures of over 30C in hot weather and 'freezing' temperatures in the winter.
Darren Johnson, chair of the London Assembly and Green assembly member, told the Huffington Post UK: "The Mayor has clearly wasted money designing new buses that then each cost £50,000 more than a standard hybrid to buy, need expensive extra staff to run, and are barely any better for the environment. He should have spent the money putting far more cleaner buses on our streets.”
London Mayor Boris Johnson previously insisted in 2011 that the cost of developing the 'New Bus for London' would be borne by the private contractors working on the new design, leading other politicians to accuse him of breaking his promise.
"If you are asking a question about the new bus which will be developed by private contractors, then I imagine that the cost of that development of that new bus will be borne by the industry," he told London Assembly members.
LibDem Caroline Pidgeon, who is deputy chair of the London Assembly's Transport Committee, told the Huffington Post UK: “The Mayor of London first promised Londoners that the research and design costs of the new bus for London would be picked up by private business.
"The reality is that over £400,000 of public money was spent on design costs alone and the first eight buses cost taxpayers a staggering £11 million.
“Having broken such a significant promise the Mayor then claimed that through bulk purchasing the new bus for London would in future only cost £250,000 per bus. Again the Mayor misled Londoners and their real cost is £354,500 per bus, which is significantly more expensive than any other hybrid bus.”
“After so many broken promises the Mayor needs to now explain why such basic faults as poor ventilation were ever permitted in the design of these incredibly expensive buses”.
A spokesman for the Mayor of London said: "It is a shame that some Assembly members continue to be critical of what is a fantastic piece of British engineering and the greenest diesel hybrid bus in the world."
"The iconic new bus for London has been very well received by Londoners and visitors to the capital, setting new standards in design and substantially reducing C02 emissions, while also supporting new jobs right across the UK."
Transport for London said: "Heatherwick Studio were the consultants on interior and exterior styling, in collaboration with the manufacturer. The brief included both the "look and feel" as well as input into the design of individual components and choice of materials used.
"Heatherwick Studio also provided quality assurance of the design and build stage of the vehicle. The total cost incurred between January 2010 and February 2012 was £428,000."
"This cost is included within the original project budget – that covered the design of the bus from scratch, construction of a full size static mock-up, construction of an engineering test vehicle, a rigorous testing regime and the manufacture of eight prototype vehicles."