German car giant BMW insists it did not "seek or receive" any assurance from the Government on post-Brexit trade before deciding to build a fully electric version of the Mini in the UK.
The new model's electric drivetrain will be built at BMW plants in Germany before being integrated into the car at Cowley, near Oxford, which employs 4,600 workers.
The car will be a variant of the three-door hatch Mini and will go into production in 2019, the year the UK is set to leave the European Union.
BMW said it had neither sought nor received any reassurances from the Government on post-Brexit trading arrangements.
Ministers faced questions last year about any assurances given to Nissan before the company announced that new versions of its Qashqai and X-Trail would be made in the UK.
There have been reports that Toyota agreed to invest in the UK after receiving a letter reassuring the Japanese carmaker over post-Brexit arrangements.
Business Secretary Greg Clark said: "This landmark decision is a vote of confidence in the determination of our Industrial Strategy to make Britain the go-to place in the world for the next generation of vehicles.
"BMW's decision recognises the strength of the excellent workforce, our record of innovation and the productive relationship between the automotive sector and the Government."
BMW said in a statement from Munich that electrification was one of the central pillars of the group's corporate strategy.
All of its models were able to be electrified, with a full electric or plug-in hybrid drivetrain being offered in addition to a combustible engine.
Additional electrified models will be launched in the coming years and beyond 2020.
Oliver Zipse, BMW's management board member for production, said: "BMW Group Plants Dingolfing and Landshut (in Bavaria) play a leading role within our global production network as the company's global competence centre for electric mobility.
"If required, we can increase production of electric drivetrain motor components quickly and efficiently, in line with market developments."
BMW said it expected electric models to account for between 15-25% of sales by 2025.
The group produces electric models at 10 plants across the world.
An electric Mini is expected to be a huge seller in the UK and overseas and the news is a huge vote of confidence in the Cowley workers.
The decision is also welcome news for the UK's automotive industry, which has been warning of rising costs if a free trade deal cannot be negotiated as part of Brexit.
Len McCluskey, general secretary of Unite, which recently agreed a deal on pensions for BMW workers to end a dispute with the company, said: "This announcement is a huge and totally deserved boost to a world-class workforce that has endured a tough few months.
"Around the world and for generations, the Mini means made in Britain.
"With the electric Mini being built in Cowley, the tradition continues but with the added bonus that this is one of the important innovations of tomorrow.
"It is fantastic news and is in no small part down to the tremendous skills and efficiency of BMW's UK workers and our members."
A handful of new jobs might be created at Cowley, which currently produces 1,000 Minis a day.
Mike Hawes, chief executive of the Society of Motor Manufacturers and Traders, said: "This latest investment is welcome news for the UK automotive sector, confirming Britain as a leader in the electric vehicle market.
"Alternatively-fuelled vehicle registrations have experienced significant growth in recent times, up 27.5% this year alone, but consumer adoption is still at a relatively low level.
"As part of a broad industrial strategy, Government must create the conditions for this technology to flourish, including infrastructure and long-term incentives for this new generation of vehicles is to be the car of choice of more motorists."
Councillor Bob Price, leader of Oxford City Council, said: "I am delighted that Plant Oxford will remain at the heart of Mini, and that the iconic product from the 1960s will go on into the future as an important part of the new generation of electric cars.
"This confirms the strong role that Mini Plant Oxford will play in the city's economy in the coming decades, and supports our drive to encourage a shift to electric vehicles to improve the city's air quality."