A Chinese-owned company is making circuit boards for F-35 warplanes flown by Britain and the US, the Ministry of Defence has revealed.
The parts, made by Exception PCB based in Gloucestershire, south west England, "control many of the F-35's core capabilities", according to publicity material produced by the MoD.
That includes "its engines, lighting, fuel and navigation systems", it said.
The MoD maintains that Exception PCB presents "no risk" to the F-35 Joint Strike Fighter supply chain and said it is an established manufacturer of circuit boards to the defence industry.
A report by Sky News revealed that Exception PCB was making parts for the F-35 on Friday.
Former Tory defence minister Sir Gerald Howarth expressed concern that a Chinese-owned company is producing parts for a classified British programme, citing fears over Chinese espionage and rivalry.
He said: "We have been completely and utterly naive about the role of China and it is only now that people are beginning to wake up."
There is no suggestion that Exception PCB or its Chinese parent, Shenzhen Fastprint, have done anything wrong.
The news comes after accusations that the Chinese state has tried to steal details about the multi-billion-pound F-35 programme, headed by US defence giant Lockheed Martin.
Equipped with a suite of highly classified sensors and other technology, the stealth aircraft is set to form a key part of US, British and other allied air and naval forces for the coming decades.
Lockheed Martin said it is "not aware of any other Chinese-owned F-35 suppliers at this time".
The MoD promoted Exception PCB as an example of a UK-based firm that forms part of the F-35's supply chain in a publication in March.
It did not mention that Shenzhen Fastprint, a company based in China, bought Exception PCB in 2013.
The MoD publication said: "Gloucestershire-based Exception PCB manufacture the circuit boards that control many of the F-35's core capabilities."
Last November, a news article published by the MoD said the company's 107 employees "manufactured the circuit boards that control many of the F-35's core capabilities, including its engines, lighting, fuel and navigation systems".
An MoD spokesman said: "Exception PCB produces bare circuit boards and as a result there are no risks associated with their product in the F-35 aircraft supply chain."