He said the workforce in Sunderland will continue to benefit from the investment planned for Juke and Qashqai.
The letter makes clear that in return for the full £80 million ($104 million), Nissan would need to "allocate production" of its Qashqai and X-Trail sport utility vehicles to Sunderland.
The company said the decision was taken for business reasons, but made clear that continued uncertainty around the UK's future relationship with the European Union was not helping it plan for the future.
Vince Cable, leader of the opposition Liberal Democrats, told Sky News the prime minister must stop "playing chicken" with Parliament and the European Union by threatening a no-deal Brexit. 'This represents a serious blow to the communities that depend on the jobs Nissan creates and supports, ' Keir Starmer, the opposition Labour Party's Brexit spokesman, wrote on Twitter.
The news was due to be announced today, but Nissan was pushed to admit it early by the swirling rumours and panic over the weekend.
While this decision is naturally not good news we want to reassure our members that job levels at the plant will remain the same even though they are being cut elsewhere in the industry.
59-Fight MMA Veteran with Pending Murder Charges Escapes from Prison Transport
Last month, Marks' wife, Ginell McDonough, was arrested in Muskegon County, Michigan and charged with harboring a fugitive. Marks was arrested in MI last month on a charge alleging he broke into Scott's home in Temple, Texas, in August.
Nissan is set to announce tomorrow that it has changed plans to build the vehicle at its plant in Sunderland, northeast England, according to Sky News.
A report by the Society of Motor Manufacturers and Traders (SMMT) said investment had effectively "stalled" amid fears over the UK's future trading prospects with the EU.
Production of diesel cars was down by 22% to 561,000 previous year.
Earlier this week the Society of Motor Manufacturers (SMMT) warned against the "devastation" of a no-deal Brexit, as it announced that United Kingdom auto production fell to a six year low of 1.52m units last year, while investment was slashed nearly in half to just £589m.
He said the money was not tied to X-Trail cars, but was linked to alternative technologies - developing electric cars and making sure the next generation of Qashqai cars could be electric. The drop in investment only foreshadows what could happen, he said.
Unite's acting national officer for the automotive sector Steve Bush said he now wanted Nissan to work with their employees regarding the future.
Nissan has confirmed that it's axeing plans to move production of the next-gen X-Trail for the European market to Sunderland as it says that Brexit uncertainty has had a hand in the decision.