Production of two new electric Mini models is due to begin at the plant in Cowley in 2026.
The move is expected to safeguard the future of the facility, as well as that of another factory in Swindon.
More than 4,000 people currently work across the two sites.
BMW is expected to say it will spend £600m on updating the Cowley plant, developing the production lines, extending its body shop and building a new area for installing batteries.
It also plans to build additional logistics facilities at Cowley and at the Swindon factory - which makes body panels for new vehicles.
This will allow two next-generation electric designs, the Mini Cooper and the larger Mini Aceman, to be built at Cowley alongside conventional cars.
A third electric model, the Countryman, will be made in Germany.
The UK investment will be backed by funding from the government's Automotive Transformation Fund - understood to be worth £75m.
With the Mini brand expected to go fully electric by 2030, BMW's decision is vital to the future of the two UK factories.
The first electric Mini was launched at the Cowley plant in 2019.
This is the latest in a series of government-backed investments designed to promote the development of electric vehicles in Britain, ahead of a ban on the sale of new petrol and diesel powered cars due to take effect in 2035.
In July, Jaguar Land Rover's owner, the Indian group Tata, said it would build a giant "gigafactory" to produce batteries in Somerset, a project expected to benefit from hundreds of millions of pounds in taxpayer support.
Stellantis has just begun production of electric vans at its Ellesmere Port factory in Cheshire; Nissan is expanding output of EVs at its Sunderland factory, while its partner Envision AESC is building a gigafactory close by.
Meanwhile Ford is investing heavily in its Halewood plant, preparing it to build electric motors."
https://www.bbc.co.uk/news/business-66745660
