Bus maker Alexander Dennis has launched a consultation on plans to cut 160 jobs at its Falkirk site.
He said the move followed a “significant drop” in demand for new vehicles in the UK.
It plans to cut 650 jobs across the UK – including 200 in Surrey, 90 in Scarborough and 200 more positions at its bases.
Unite Scottish secretary Pat Rafferty has said the union will not allow “wild cuts” to go unopposed.
Managing Director Paul Davies said: “We have no choice but to implement these difficult decisions”.
He added that it was necessary “to protect the future health of the company”.
“We remain confident that the situation will improve over time, and we are well positioned to take advantage of that when it does, but for now we need to adapt to our new economic reality. ”
He called on the British and Scottish governments “to urgently introduce meaningful support”