Given that its not going to happen overnight its already on its way in London. I have ridden on hydrogen, electric and hybrid red buses in London and the Tube system is electric already. Congestion charging keeps a lot of vehicles out of the centre. But I'm not sure that there is either a viable electric taxi at present (that has a range comparable to the sorts of distances black cabs do in a day) and it won't be popular with the taxi drivers who would need to scrap all their black cabs and buy new with the added premium that electric vehicles carry.
Taxis are not a good solution though. They do a lot more mileage than the equivalent journey by private vehicle. For example if I am going somewhere by private vehicle I do the mileage there and the mileage back. If I do it by taxi, the taxi does mileage from its present location to mine, does the mileage there, then does more mileage again looking for its next fare with the whole cycle repeated on the return journey.
Every time I see any film footage of London it's awash with cars,taxis,buses,trucks,etc all running on ICE's diesel or petrol,there maybe alternatives but they're a small minority.If the threat of danger,perceived or real,is removed it opens the way for other transport forms.
So lots more miles than is necessary and even if they are electric they are still producing pollution, but at the power station rather than on the streets.
Taxis are not
a very inefficient system of transport.
We are going to pollute,I'm polluting now by using the internet,it's about minimising it.ATM we're actively promoting unnecessary pollution by the way we promote both long and short journeys and by concentrating the pollution where it does the most damage,where the most people are,in towns and cities.
the only real difference between public and private is whether you pay for it through fares or taxes.
No it isn't,private companies are there to make a profit either for the owner or shareholders the more profit the more investment in them,corners are cut services are trimmed,that's why they cut services to rural areas or non profit making routes.
Public transport is run as a service to the public and for the public.
Either way you are paying.
But not as much if a service is provided efficiently as non profit making or only making small profits.
The problem is capitalism is seen as the solution when it's problem.
BTW there are other cities outside of London that don't benefit from London's privileges Edit