From Saturday 26 April route 10 will become the latest in the capital to be served entirely by New Routemasters.
These are the cleanest and greenest diesel electric hybrid buses in the world and are part of a comprehensive programme to reduce emissions from London's bus fleet.
Currently, five bus routes in London are served by around 140 New Routemasters.
By 2016 there will be 600 of these new buses on London's streets.
Route 10, which runs 24-hours a day and is operated by London United, runs between Hammersmith Bus Station and King's Cross St Pancras via Olympia, High Street Kensington, Knightsbridge, Hyde Park Corner, Marble Arch, Oxford Circus, Tottenham Court Road and Euston.
Buses on route 10 will operate with the rear door open and a conductor on the rear platform for the majority of the day on weekdays (6am-6pm Monday to Friday).
In the evenings and at weekends the rear platform will be closed when the bus is moving but all three sets of doors will be open and closed by the driver at bus stops.
During peak hours, 23 of the new buses will be in passenger service to carry the 19,000 people who travel on the route each week day.
The next route to be converted will be the 38 along with night service N38, operated by Arriva, which will see more New Routemasters being introduced on a phased basis, with full conversion expected by the end of May.
It was the route on which the first prototype New Routemaster entered service in February 2012.
The route 38 runs between Victoria Station and Hackney, via Hyde Park Corner, Green Park, Piccadilly Circus, Bloomsbury, Islington, Dalston, Hackney Central Station and Clapton Pond.
The route N38, which operates at night, has an extended service running additionally via Lea Bridge, Leyton (Bakers Arms) and Walthamstow Central.
Once converted, buses on route 38 will operate with the rear door open and a conductor on the rear platform for the majority of the day on weekdays (6am-7pm Monday to Friday) on the busiest section of the route between Islington and Victoria.
On the remainder of the route, in the evenings and at weekends the rear platform will be closed when the bus is moving but all three sets of doors will be open and closed by the driver at bus stops.
During peaks hours, 59 of these state of the art buses will be in passenger service to carry the 42,000 people who travel on the route each week day.