Which begs two important questions. First, how are we going to produce the electricity to power all these new cars, and secondly, is this really the answer to cutting environmental pollution?
Retired civil engineer David Myles has his doubts. He says in order to generate enough electricity to keep them all running, the equivalent of nine new nuclear power stations would need to be built. He adds that converting other motor vehicles to run on electric powers would require a further nine power stations.
The alternative, he adds, would be for the extra electricity to be generated using fossil fuels, which might not necessarily bring the environmental benefits their supporters are hoping for.
"In Germany, 40 per cent of all electricity is generated by coal-fired power stations of which half use lignite, the dirtiest fuel known to mankind, and these are still being built," says Mr Myles.
"Nobody wants to mention to the emperor the problem with his new clothing."
Prof Liana Cipcigan, of Cardiff University, is one of the UK's leading experts in electric vehicles. She says that while a wholesale switch to electric cars will lead to extra pressures on the national grid, suggestions that vast numbers of new power stations will be required to service them are wide of the mark.
"A lot of these fears are based on misunderstandings," says Prof Cipcigan.
"For example, this assumes that all the demand would come at the same time, but it is extremely all these cars would be charged at the same time, people would charge them at different times."
"The increase in the number of electric vehicles will lead to higher demand for electricity, but the grid will evolve because it will not happen overnight. It will happen by 2040, or by 2034 if we want to push it forward.
Prof Cipcigan adds that battery technology will mean that future electric cars will be able to play a role in smoothing out demand for electricity throughout different times of day.
"They can discharge electricity into the grid, as well as being charged by it," she says. This means, if they are plugged in when they are not being used, that electric cars can be charged at times of low demand, when electricity is cheap, and then feed power back into the grid when demand is high.
The National Grid has modelled a number of different scenarios, including one based on the assumption that there could be 25 million plug-in vehicles on the road by 2050.
Russell Fowler, market insights manager at National Grid, says if that scenario came true, it could lead to an increase in demand for electricity of 30 per cent.
He says: "As the numbers of electric vehicles increase, their peak time electricity demand is one of the challenges that will need to be met.
"You could argue that millions of motorists all needing to charge their electric vehicles would require lots of new power stations just to meet this surge in demand.
"But in fact this is where better consumer engagement and advances in technology both have a part to play."
He says if everybody chose to charge their vehicle at the same time, it would indeed create a 'runaway' peak demand that would need to be managed.
But in reality, this was unlikely to happen.
"People arrive home at different times and have different routines, with only one in five expected to charge at peak times," he says.
"It’s a little bit like every home having a kettle, but we don’t all make a cup of tea at the same time."
Mr Fowler says solutions will lie in a combination of incentives to encourage people to charge their cars at different times, and systems that make the process of charging as simple and automated as possible. This would be likely to involve the use of mobile phone applications.
"Consumers would likely be just a couple of clicks on an app away from getting the whole thing done with the minimum of fuss," he says.
The other difficulty is that if every household has one, two or maybe three electric cars, where will they be charged? If you live in a suburban house with an ample driveway this probably won't be a problem, but if you live in a flat or a Victorian terrace with no drive it will obviously be more difficult.
Mr Fowler says half of households in Great Britain are without off-road parking.
Mr Fowler predicts that as technology develops, chargers will become much quicker and more powerful.
"We also assume that chargers will be smart-enabled, in other words they can talk to each other," he says. This will enable both consumers and energy companies manage demand for power in the most effective way.
Of course, if Britain switches en-masse to electric vehicles, it will probably spell the end for the petrol-station forecourt, although owners of the estimated 500,000 classic or historic vehicles on UK roads may have something to say about that.
However, Mr Fowler believes that, advances in charging technology permitting, some of these forecourts could be used for quick blasts of high-speed charging.
"Several companies are investing in ‘flash battery’ technology that could allow a vehicle to run for a long distance from a five-minute charge," he says.
"If successful, this super rapid electric vehicle charging could support the introduction of more forecourt charging sites."
While electric cars will certainly mean more power will be needed in future, it should also be noted that general demand for electricity has been in decline for some years. On the other hand, one of the future scenarios modelled by the National Grid would require large-scale fracking for gas-fired power stations.
Another factor, though, is that manufacturing electric cars produces a larger carbon footprint than traditional petrol or diesel cars.
The American-based Union of Concerned Scientists says: "Manufacturing a mid-sized electric vehicle with an 84-mile range results in about 15 per cent more emissions than manufacturing an equivalent gasoline vehicle.
"For larger, longer-range EVs that travel more than 250 miles per charge, the manufacturing emissions can be as much as 68 per cent higher."
A 2017 study showed that in Germany, where more than half the country's electricity was generated from coal and gas, an electric car owner would need to drive 62,000 miles before there was any environmental benefit, due to the extra damage caused at the manufacturing stage. However, if the car could be charged using only 'green electricity', this figure would fall to 18,411 miles.
Another issue is what happens to the huge batteries when they reach the end of their useful life. Prof Cipcigan says recycling technology has come on in leaps and bounds in recent years. She says it will also be possible to reuse them for electricity storage, which will in turn enable greater use of renewable energy sources.
The Government clearly believes that electric cars are the future of a greener transport policy, but sceptics will point out that little more than a decade ago our political leaders were trying to convince drivers to switch over to diesel.
While electric cars are certainly more commonplace than they were a decade ago, persuading millions of drivers to make the switch is a big challenge. As will producing the energy to power them all.
But Prof Cipcigan is in no doubt that electric cars are the future, and that 30 years from now people will be wondering what all the fuss was about.
"The change to electric vehicles will lead to an increase in demand on the National Grid, but the Grid will be able to cope through innovation," she says.