A new fleet of electric buses is being introduced on two busy commuter bus routes serving Waterloo Station.
Former Mayor of London Boris Johnson announced last year that routes 507 and 521 would be converted to all-electric operation.
This week the first of the new fleet of Chinese-built BYD buses was brought into service as the diesel fleet is phased out.
The 51 buses – built and maintained in a £19 million deal – form the single largest fleet of full size electric buses in Europe.
New electric charging points have been installed at Waterloo Bus Garage on Cornwall Road.
As well as being notable for their electric power, the new buses are also the first on the TfL network to feature at-seat USB sockets for passengers to charge their mobile phones.
Electric buses were first trialed on the 507 and 521 in 2013.
The 507 and the 521 are the last remnants of the once extensive Red Arrow network of bus services introduced in 1965.
To mark the 50th anniversary, Go-Ahead recently painted one of its Mercedes Citaro buses in a commemorative livery.
A book – London's Red Arrow Buses: 50 Years of Service – has also been published this year.