The Royal Navy is moving fast to retrieve the airframe of a UK F-35B fighter jet, after it crashed into the Mediterranean Sea on Wednesday.
Experts fear stealth technology found within the wreck could be used against Britain and its allies if adversaries are first to retrieve the missing plane.
The pilot ejected safely from the £100m British aircraft, which had been one of eight on aircraft carrier HMS Queen Elizabeth.
Gareth Jennings, an aviation expert from Janes, said "exotic metals" and other elements of the F-35 design could be of great value to Western opposition.
He said: "If anyone could recover that aircraft, the concern would be that they could then reverse-engineer those composites, those structures, not only to work out how to maybe defeat the aircraft, but it could also enhance their own domestic aviation industries."
Russia was among the list of states that could take an interest in the crash site, according to Mr Jennings.
The US, which has its own F-35s onboard HMS Queen Elizabeth, will be "just as keen as the British to ensure that no unauthorised eyes get to see that aircraft", said the expert.
The Ministry of Defence won’t confirm whether it knows the exact location of the downed F-35, but insists no other aircraft was involved in the crash.
The department said an investigation is likely to focus on technical or human error.