The first electric black taxis have arrived on the capital's roads as the London mayor pushes to improve air quality.

It is hoped more than 9,000 of the £55,599 cabs will be in service by 2021.

The TX can travel 80 miles on a single battery charge and is fitted with a 1.5 litre petrol engine to assist longer journeys. The cab has six seats, contactless card machines, Wifi and USB charging.

The London Electric Vehicle Company (LEVC) says it will save drivers on average £100 in fuel a week.

Concern has been raised about the small number of electric charging points in place throughout the capital.

An £18m scheme to install 75 rapid charging stations by the end of this year - which can load vehicles in 30 minutes - is reportedly behind schedule.

"The whole thing is just a farce, you couldn't make it up," says Steve McNamara, General Secretary of the Licensed Taxi Drivers Association.