London (CNN Business) The British government promised Nissan up to £80 million ($104 million) as it sought to reassure the Japanese carmaker about the future of its UK operations after the Brexit vote in 2016.

The offer was included in a letter from Business Secretary Greg Clark to former Nissan Chairman Carlos Ghosn dated October 21, 2016. The letter said UK support was contingent on Nissan building two models in England.

The letter, which was released by the UK government on Monday, has long been the subject of speculation.

Nissan NSANF The government had previously refused to detail its arrangements with, sparking concerns that a special deal had been struck to ensure continued investment at the company's massive plant in Sunderland. UK voters chose to leave the European Union in a referendum in June 2016.

Clark wrote in the letter that supporting carmakers would be a priority during Brexit negotiations, and that he would ensure that Nissan could continue to export to and from the European Union.

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