BMW has announced it is to upgrade its Hams Hall engine plant in Warwickshire.
The company confirmed it would install a production system for a new generation of low emission petrol and diesel engines.
Unite union regional officer Simon Powell said it would secure the long term future of the 800 employees who work at the factory.
The Hams Hall plant, near Birmingham, opened 10 years ago and has produced engines for the Mini since 2006.
'Vote of confidence'
"Lots of hard work has taken place with the local management team," said Mr Powell.
"There was no guarantee we'd get the investment because BMW has engine plants in other parts of Europe.
"So it's a significant vote of confidence for workers in the UK."
In June, BMW announced a plan to invest £500m in UK car production over the next three years, safeguarding more than 5,000 jobs at Hams Hall, the assembly base in Oxford and the pressings plant in Swindon.
Hams Hall set a new annual production record in 2010 with 385,051 engines - about 16% of total UK engine production.
The plant was the first BMW engine production facility to be built outside Germany and Austria.