THOUSANDS of Oxfordshire jobs in science and manufacturing – including at Oxford’s Mini plant – would be at risk if Britain leaves the European Union (EU), it is warned today.

Prime Minister David Cameron, business leaders, universities, the city’s MPs and union bosses said a vote to leave on the June 23 referendum could push up costs and make it harder for foreign workers to bring their skills to the county.

It came after German car giant BMW, which runs the Mini plant in Cowley, told staff in a letter that without EU free trade agreements, its operating costs for imports and exports in the UK could rise.

Yesterday the Prime Minister said a vote to leave would “put at risk a great success story”, with union bosses at Unite warning of a threat to jobs in Oxford, where the company employs about 5,000 people.

Mr Cameron said: “The UK car industry is doing better than ever before.

Across the country, around 150,000 people are employed in the industry directly, including the thousands of jobs at BMW Mini in Oxford. 

“Last year, the UK exported a record number of cars, and more than half of those went to the EU market. 

“That’s why we need to pay attention when our car industry tells us clearly – we are better off in a reformed EU. 

“Leaving the EU would be a leap in the dark and would put at risk a great British, and Oxfordshire, success story.”

Since production of modern Mini models started in 2001, more than 2.5 million of the cars have been built in the city and exported to some 110 countries.

Chris Bond, a Unite convenor and plant worker of 42 years, said: “Without a doubt, the referendum is going to be be crucial for jobs in Oxford. We will be putting out the message strongly that Britain should be staying in. People are concerned about the effects of leaving, but they appreciate BMW’s honesty.”

Oxford East MP Andrew Smith said: “It would be a disaster if BMW stopped production in the city but I don’t believe it would stop making cars at Cowley if we left the EU. The question uppermost in car workers’ minds is bound to be ‘why take the risk?’.”

Speaking yesterday on Radio 4’s Today programme, BMW board member Dr Ian Robertson warned an exit would trigger “a time of uncertainty” but stopped short of saying there would be job losses.

He said: “We enjoy the free movement of vehicles, the free movement of components and – very importantly – the free movement of labour to support our factories around Europe. At our Oxford plant we have more than 70 different nationalities. 

“We are not saying leaving the EU would result in higher car prices or a drop in wages, but there would be a time of uncertainty.”

His comments were echoed by Rob Lindley, Harley-Davidson’s Europe, Middle East and Africa director – based in Cowley – who added: “There is a lot more risk than there is opportunity in the idea of Brexit.”

Oxford University has also supported remaining in the EU, with Oxford Brookes University vice-chancellor Professor Alistair Fitt saying it was “vital” to higher education.

According to Brookes, about 14 per cent of its academics are European nationals and a quarter of its grants and contracts came from EU bodies.

Science chiefs also warned millions in funding from the EU for “world-leading science” in Oxfordshire would be at risk.

Professor Steve Cowley, chief executive of the JET fusion power facility in Culham, which employs 1,100 staff, said: “Two thirds of our funding comes from the EU, so for us a vote to leave would create a very tricky situation. 

“The EU has been incredibly important for science. If we want to remain a forward-looking country we cannot do that alone.”

Oxford West and Abingdon MP Nicola Blackwood, chairman of the House of Commons Science and Technology Committee, last month said Britain’s EU membership “protects lifesaving research and key research and development jobs”.