The first A321 LR takes off on its flight test in Hamburg, Germany

Airbus issued its strongest warning yet over the impact of Britain's departure from the European Union, saying that a withdrawal without a deal on future trade would force it to reconsider its long-term position in the U.K.

In a memorandum issued late on Thursday, Airbus said softer plans for a transition period ending in December 2020 were still too short for the planemaker to adapt its supply chain and would prevent it from expanding its U.K. supplier base.

Airbus, which makes wings for all its passenger jets in the U.K., said that leaving both the EU's single market and customs union immediately and without any agreed transition would lead to "severe disruption and interruption" of U.K. production.

"Put simply, a no-deal scenario directly threatens Airbus' future in the U.K.," Tom Williams, chief operating officer of Airbus Commercial Aircraft, said.

Airbus is accelerating measures to reduce risks, he said in the statement, without elaborating.

In March, Williams told staff in a video that Airbus was looking at buying more parts to build up a buffer stock to cope with potential disruption when Britain leaves the EU on March 29, 2019.

Echoing calls from Germany's Siemens earlier this week, Airbus said it needed immediate details on how its operations would need to be organized.