Airbus SE threatened to pull its U.K. investments if Britain walks away from the European Union without a deal, upping the stakes for Prime Minister Theresa May as she fights to deliver a Brexit that won't wreck the country's economy.

In the starkest warning yet from any major company, the aerospace giant said late Thursday that a departure from the single market and customs union without a transition agreement would lead to "severe disruption and interruption of U.K. production." Airbus, based in Toulouse, France, would be forced to "reconsider its investments in the U.K., and its long-term footprint in the country."

"This is a dawning reality for Airbus," Tom Williams, chief operating officer of Airbus Commercial Aircraft, said in an emailed statement. "Put simply, a No Deal scenario directly threatens Airbus' future in the U.K."