The British government helped to secure a more than 240-million pound investment from Toyota in its English plant with a letter reassuring the Japanese carmaker over post-Brexit trading arrangements, two sources told Reuters.

Toyota said on March 16 it would install its new car platform at its Burnaston plant.

One source, who is familiar with the letter, said that Toyota delayed the decision due by the end of December while it weighed up a number of factors including Brexit.

The business ministry has confirmed the existence of a letter but refused to release it.

The source said the letter was similar to one sent to Japanese carmaker Nissan last year when it decided to build two new models at its northern English plant.

The document sparked public and lawmaker concern about secretive deals. The source, who did not say when the letter was sent, said it contained several reassurances.

“They received a similar set of warm words as Nissan on electric vehicles, commitment to further training and to ensure the competitiveness of the UK automotive industry,” the source said.

A Toyota spokesman declined to comment on whether it had received such a letter. He referred to the company’s March 16 statement which said the British government was providing funding for training and research and development.

Toyota also said at the time that “continued tariff-and-barrier free market access... will be vital for future success.”

Britain said in March it would back up the investment from Toyota, which builds roughly 10 per cent of Britain’s 1.7 million cars, by spending 21.3 million pounds to support skills and training, research and development and innovation, subject to an independent assessment.

A spokesman at the business ministry declined to provide any comment for this story. Business minister Greg Clark said last year that assurances offered to Nissan were available to other firms.

Reuters made a freedom of information (FOI) request to the business ministry to see documentation relating to the investment decision, which the ministry said included a letter.

In its response, an official at the ministry refused to release the letter and a company briefing note, saying the information was “both highly commercially sensitive” and “would be likely to cause harm to the company’s commercial interests if disclosed.”

Meanwhile, Mr Clark has refused to publish the Nissan letter. He said he will release the information when it is no longer commercially confidential.

Many of the world’s biggest car firms are worried about the long-term viability of their British plants and are using their upcoming investment decisions to push for promises to maintain free trade after Britain’s exit from the EU, which is due to take place in March 2019.

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