Around 1,900 jobs are expected to go at BAE Systems on Tuesday as management is due to tell workers of swingeing cuts to its workforce.
The bulk of the jobs will go at the company's factory at Samlesbury, near Preston and the neighbouring Warton site. Jobs will also go in East Yorkshire, but the majority of cuts are expected in Lancashire.
Parts for the Typhoon jet are built by workers at the company's factory at Samlesbury, with final assembly and testing work at the Warton site, which employ around 11,500 people across both sites.
On Monday, the company has confirmed governments in the four partner nations of the Typhoon's jet-building consortium, made up of the UK, Germany, Spain and Italy, are to buy aircraft over a longer period of time, slowing production.
Fylde MP Mark Menzies told the Lancashire Evening Post on Monday that the scale of cuts would be "devastating" for Lancashire's defence industry.
He said he knows many of the workers "and I know how passionately they care about the jobs they do."
"This is about Typhoon and the level of orders and while the slowdown has provoked this decision I hope future export orders will keep production going for some considerable time to come," he told the LEP.
Ben Wallace, MP for Wyre and Preston North, said there are tremendous opportunities for export of the Typhoon, but unfortunately the buyers are not yet ready.
Trade union leaders at the Lancashire factories said news of the slow-down of Typhoon work had been "the worst-kept secret" among the workforce.
It is believed the company will make an announcement on Tuesday.
On Monday, BAE told staff that news of the looming cuts were "media speculation" although workers will be called to meetings on Tuesday to be informed of the news.
The Unite union said it needed immediate clarification of which sites will be hit and pledged to press for redundancies to be voluntary.
The cuts come on top of more than 1,300 job cuts announced over the last 12 months on the back of the government's decision to scrap the Harrier and Nimrod projects, which employed thousands of staff across BAE.
A statement from BAE Systems said it was talking to trade unions about ways to "continue to help in delivering efficiency improvements" and confirmed it was slowing the production rate of Typhoon.
It added: "BAE Systems recognises that the long-term future of Typhoon is based on its export potential and therefore we need to ensure we are in the best possible position to secure those opportunities - extending the production programme will help us achieve this.
"We remain committed to making Typhoon a success both in the UK and overseas markets."
The company employs 40,000 staff in the UK and just under 100,000 globally.
