Millions of petrol and diesel cars could have compulsorily scrapped if the Government is to hit its latest greenhouse gas reduction targets.
The warning comes from Ian Henry of AutoAnalysis after Boris Johnson’s announcement that by 2030 the UK aims for carbon emissions to be at least 68pc lower than 1998 levels.
The Climate Change Committee, which advises the government, said this would require 46pc of cars on British roads to be electric within a decade, and 97pc of new vehicles sold to be electric.
The Society of Motor Manufacturers and Traders (SMMT) has questioned how realistic the goal was.
At the start of this year there were 35.1m cars on UK roads, of which just 237,000 where battery or plug-in electric vehicles capable of running in zero-emission mode.
This means 16m petrol and diesel cars will have to be scrapped and replaced by electric vehicles to hit the 46pc level.
This is a major challenge even with a ban on the sale of new cars driven solely by petrol or diesel engines being brought forward last month by five years to 2030.
Latest industry data shows just under a quarter of new car sold in November had full or part-electric drive trains, but just 5.8pc were entirely battery powered, although this level is rising.
As the average lifespan of a car in the UK is 14 years, and if new vehicle sales return to pre-pandemic levels of about 2m a year, it is unlikely that electric cars will replace conventionally powered ones at a fast enough rate to hit the target.
Mr Henry said: “The ambition for reducing emissions great but actually doing it is incredibly difficult. How is the Government going to force so many cars off the road? Could we see compulsory scrapping?
“Convincing drivers that there is the infrastructure to support electric vehicles so they are willing to buy them is another massive question.”
He also questioned whether there will be enough electric cars produced to meet the target, especially if other countries adopt similar targets.
The Government has yet to provide any detail on how the new target will be achieved or what it will cost.
Mike Hawes, SMMT chief executive, added: “Even with an accelerated end of sale date for petrol and diesel cars and vans, and the current range of incentives, new EV uptake would need to increase at least 10-fold to reach such a bold target.
“Whether or not this is realistic in a globally competitive marketplace for these products, the Climate Change Committee underlines the scale of the challenge and rightly calls for a clear plan and investment strategy from government.”
The car industry - which has invested hundreds of billions in electric cars globally - supports the transition to electric vehicles.
However, automotive insiders privately labelled the targets given by the Climate Change Committee as “unachievable” with current levels of government support.
The Prime Minister’s plan for a green industrial revolution included £1.3bn to help fund infrastructure to charge vehicles, and £582m for incentives to encourage motorists to buy electric vehicles, which are more expensive to buy.
Under the existing incentive scheme which offers grants of up to £3,000 to reduce the cost of electric cars, the £582m could help fund as few as 200,000 new vehicles.
Jamie Hamilton, head of electric vehicles at Deloitte, said: “In order to get this volume of electric vehicles on the road by 2030, mass adoption will be required over the next two to three years.
"This will only happen if consumers are convinced that the charging infrastructure is in place to support the move to electric.”
The developments came as SMMT data showed that new car sales in November went into reverse as the second lockdown meant dealers closing their doors, with a 27.4pc drop in new vehicle registrations.
Motorists received the keys to 42,840 new cars last month, more than a quarter down on the same period a year ago.