An electric version of London's black cab will be on sale by the end of next year.
The vehicle, built by black cab maker LTI Vehicles, is called the TX4E and is said to have a range of 100 miles and top speed of 50mph. It will use lithium ion batteries and estimates suggest it will cost around 4p per mile to run.
However, it will be more expensive to buy than a conventional TX4, which starts at around 28,000. This means that few drivers are likely to use the vehicle, unless current emission regulations change.
At present, a conventional TX4 is exempt from emissions-based charging such as London's Congestion Charge, even though the automatic model emits more than the 225g/km of carbon dioxide - the limit above which drivers must pay 25 to enter central London.