Boris Johnson's Routemasters branded a waste of money at £7.8m for five buses

The bill for Boris Johnson's new generation of Routemasters has come in at £7.8 million for just five buses, it emerged today.

Transport for London said the initial outlay included design and development costs, covering all research, prototypes and testing.

Critics suggested the "hop-on, hop-off" vehicles, which were a key mayoral election pledge and were intended to replace the scrapped bendy buses, were a waste of money.

No decision has been made on additional orders. If more are commissioned, the cost could come down significantly. A conventional double-decker costs £190,000 to build.

TfL sources said they anticipated "at least a couple of hundred" new hybrid Routemasters on the roads in the next few years.

Mr Johnson wanted to find a design based on the original red buses that served the capital for 50 years until they were withdrawn by his predecessor, Ken Livingstone, in 2005 as they were inaccessible to wheelchairs and pushchairs.

The Mayor chose a blueprint by car-maker Aston Martin and architects Foster & Partners, with wooden floors, a glazed roof with solar cells and a rear platform.

This was shelved last year and the contract to create a "21st-century icon" for London went to Wrightbus which will design, test and build five new buses by 2012.

Each will have three entrances, including a "hop-on, hop-off" platform and two internal staircases, and will carry 87 passengers.

Sadiq Khan, Labour MP for Tooting, said: "This is an extraordinary and wasteful amount to spend when fares are rising and important services like ticket offices are being cut. More than £1 million on each bus, replacing completely serviceable buses just based on the design, is a poor choice of priorities."

A spokesman for Mr Johnson said: "The project represents good value for money in terms of fuel economy and lower emissions. TfL's investment covers all research and development costs, prototypes, rigorous testing and five vehicles. We expect to have hundreds of these bespoke hybrid vehicles on our streets in years to come."

TfL commissioner Peter Hendy said the start-up cost would be spread across "hundreds" of new vehicles, and the final cost of a Routemaster is expected to be "comparable with a standard double-deck hybrid".