Airbus has said it is running out patience with the government and a “no-deal” Brexit would mean “chaos at the borders”.
The company employs 14,000 people at several sites including Bristol, Stevenage, Portsmouth and north Wales, but another 110,000 jobs are also vulnerable at firms supplying the aircraft maker.
In one of the most significant interventions by a major manufacturer since the referendum two years ago, it published a “risk assessment” on its website saying it would “reconsider its investments in the UK, and its long-term footprint in the country” if Britain left the single market and customs union without a transition agreement.
Speaking to Sky News, the company’s senior vice president Katherine Bennett said: “We would see it as chaos at the borders.
“Our parts move across the borders sometimes up to two or three times, perhaps going into a satellite that we build here in the UK or the wings that we make here in the UK.
“We don’t want them to be affected by friction at the borders.”
Ms Bennett said Airbus was “running out of patience”.
She said EU member states, as well as the UK, need to understand the importance of the way Airbus works.
“It’s putting pressure on all sides, it’s not just the UK,” Ms Bennett said.
“We are an international business and the EU 27 need to understand the importance of integration and the way we work.”
Airbus says the current planned transition period to December 2020 was too short for businesses to reorganise supply chains.
Tom Williams, chief operating officer of Airbus Commercial Aircraft, said: “In any scenario, Brexit has severe negative consequences for the UK aerospace industry and Airbus in particular.
“Therefore, immediate mitigation measures would need to be accelerated.
“While Airbus understands that the political process must go on, as a responsible business we require immediate details on the pragmatic steps that should be taken to operate competitively.
“Without these, Airbus believes that the impacts on our UK operations could be significant.
“We have sought to highlight our concerns over the past 12 months, without success.
“Far from ‘project fear’, this is a dawning reality for Airbus. Put simply, a no-deal scenario directly threatens Airbus’s future in the UK.”
The risk assessment says: “A no-deal Brexit must be avoided, as it would force Airbus to reconsider its footprint in the country, its investments in the UK and at large its dependency on the UK.
“Given the ‘no-deal/hard Brexit’ uncertainties, the company’s dependence on and investment in the flagship Wing Of Tomorrow programme would also have to be revisited, and corresponding key competencies grown outside the UK.
“This extremely negative outcome for Airbus would be catastrophic.
“It would impair our ability to benefit from highly qualified British resources, it would also severely undermine UK efforts to keep a competitive and innovative aerospace industry, while developing high-value jobs and competencies.”
The warning has sparked claims that “Project Fear” – a term Brexit supporters use to refer to what they view as instances of scaremongering – has reared its head once more.
John Longworth, co-chair of the campaign group Leave Means Leave, said: “Airbus are claiming that they might relocate out of the UK because of uncertainty, but if we leave the customs union nothing will change as tariffs on aeronautical products are zero.
“They are also claiming that they may move production to countries outside the EU, which clearly can have nothing to do with Brexit.
“The best way to ensure certainty is to declare for WTO terms now and prepare to leave the EU in March 2019, an outcome companies like Airbus are fervently seeking to frustrate.
“No doubt we will see more of these scare stories over the coming months as multi-nationals seek to undermine the democratic decision of the British people in order to protect their own narrow, vested interests.”
Downing Street insisted it had a “good dialogue” with Airbus and “continues to speak to them”.
A spokesperson said the business department was “speaking with” officials from the aerospace giant on Friday.
Earlier on Friday, Number 10 defended the “significant progress” made in negotiations with the EU “to ensure trade remains as free and frictionless as possible, including in the aerospace sector”.