Designs which could see the iconic Routemaster bus being returned to regular service have been unveiled.
Plans for an emission-free Routemaster, using a driver and conductor, were outlined by Autocar magazine.
The buses would carry 76 passengers and there would be a ramp for pushchair and wheelchair access.
The Mayor of London said the design would increase fares and did not address the safety and accessibility issues which led to the fleet's demise.
The majority of the original fleet of Routemaster buses were withdrawn in 2005.
Bus designer Capoco was asked to come up with a design for a new Routemaster by Autocar.
In the plans, electric motors would drive the bus and be powered by battery packs which, in turn, are charged by a hydrogen-fuelled engine and generator.
The bus would carry 48 people on the upper deck and 28 on the lower and be built from lightweight materials.
MP for Henley Boris Johnson, who is the Conservative candidate for London mayor, backed the plan which he said was the "shape of the future".
But a spokesman for London Mayor Ken Livingstone said the cost of the new buses would be an extra £600m a year.
He said: "This is typical Boris Johnson incompetence.
"Now he has unveiled his bus scheme it would mean single bus fares going up from 90p to £1.50 and a weekly bus pass from £13 to £22."
Autocar editor Chas Hallett said: "We approached Capoco to create a new-generation Routemaster bus to our brief.
"Resurrecting the bus conductor would improve security for the public and for the driver."
Routemasters still operate on two tourist routes in London taking passengers past some of the city's top attractions.