The Mayor of London promised “value for money” as he announced the launch of 50 all-electric buses in the capital.

Speaking at Mayor’s Question Time last week, Boris Johnson told assembly members that two further bus routes would operate entirely with electric buses from autumn next year, reducing 408 tonnes of carbon per year.

“We are going to get value for money,” Mr Johnson told members, who also queried the manufacture of the vehicles, which is yet to be decided.

As well as the conversion of routes 507 and 521 to electric, all 300 single deck buses in central London are set to be zero emission by 2020.