The money will be invested in manufacturing operations by the end of 2015 at the German car maker's plant in Oxford, steel body pressings operation at Swindon and engine plant at Hams Hall near Birmingham.
The company also announced further volume growth with up to 10 different Mini models, with the potential for additional production capacity at Oxford.
The news comes on top of an announcement last July of a £500m investment and means additional job security for the 5,500 UK Mini workers, the company said.
BMW Group board of management member Harald Krueger said: "This brings the total to £1.75bn since 2000.
"Over the last 11 years, Mini has been a unique global success and the BMW Group has even greater plans for the future development of the brand.
The company's Oxford facilities have played a major role in the car's success, with exports to over 100 countries around the world.
"This additional investment is great news for all our employees in the UK and shows the BMW Group's commitment to Britain as a vital manufacturing base for us," Mr Krueger said.
Business Secretary Vince Cable told Sky News: "It does tell a very good story and this is on top of existing investment commitments by this firm in Minis.
"Car making is a really big, industrial success story. We are talking tens or possibly hundreds of thousands of jobs in the companies and in the supply chain."
BMW said the extra volume for its growth plans for the Mini and the complexity of new models means that additional production beyond Oxford's maximum capacity was needed in the medium term and the company was now considering how to achieve this.
"Our preferred option is to establish a contract manufacturer as a satellite production as close to our UK operations as possible, at the Nedcar plant in the Netherlands, with whom BMW is in discussions," Mr Krueger said.
Unite assistant general secretary Tony Burke said: "This major boost in investment is tribute and reward for the dedicated and hard-working workforce at Oxford, Swindon and Hams Hall.
"The British car industry is once again a ray of sunshine in gloomy times for British manufacturing."