Motorists are being encouraged to use a horse and cart during rush hour to help protect the environment.
Private cars are said to produce 10% of all the UK's CO2 emissions
The initiative will begin in London before visiting Birmingham between 30 July to 1 August and Manchester between 13 to 15 August.
It will pick up its first passenger, BBC London presenter Vanessa Feltz, from her home in St John's Wood before taking her to the BBC London studios.
The cart will be pulled by Clarkson, a 15 year-old English Traditional Cobb.
The chassis has been restored from a late 19th century, French built Victoria carriage.
It is equipped with a small fridge, laptop port and even a sound system all powered by solar energy.
The novel mode of transport is being offered by an organic yogurt maker.