The Navy have launched an investigation after an aircraft technician's girlfriend was found hiding in a cupboard after he smuggled her onto the airbase.
The woman is said to have been caught hiding semi-naked among her lover's jumpsuits at RNAS Yeovilton in Somerset.
He is said to have sneaked her into the Somerset base in the boot of his car when he returned from Christmas leave.
The Navy base is home to the Commando Helicopter Force and its Merlin helicopters, as well as a number of Wildcat helicopters - which are due to join aircraft carrier HMS Queen Elizabeth when it is deployed to the South China Sea later this year.
The technician, who is part of the Commando unit, admitted to his superiors the woman - who was born in Indonesia but is a Dutch citizen - is his girlfriend.
Concerns were raised on the base over the security breach with colleagues fearing the woman could have been exposed to vital secret information about the airbase.
The woman is said to have been caught hiding among her lover's jumpsuits at RNAS Yeovilton in Somerset (pictured)
The Navy base is home to the Commando Helicopter Force and its Merlin helicopters (pictured), as well as a number of Wildcat helicopters
The Wildcat helicopters are due to join aircraft carrier HMS Queen Elizabeth (pictured) during its deployment to the South China Sea later this year
But the Ministry of Defence denied that there was any suggestion of espionarge.
A spokesperson for the MoD told Mail Online: 'The Royal Navy takes any breach of security or Covid guidelines extremely seriously.
'We are investigating the incident but the individual is a European national and there is no suspicion of espionage.'
The Sun reports that the woman was escorted from the base by armed guards and is said to have left the UK immediately.
A Navy source also told the paper the woman was an 'unauthorised foreign national on Ministry of Defence property' and described the incident as 'an astonishing breach'.
According to the Sun, the technician, who is serving with 847 Naval Air Squadron, told Navy bosses he first met the woman on holiday in 2019.
The incident constitues a major security breach at the airbase.
The MoD have launched a probe into the incident and discussions about the penalty for the aircraft technician are ongoing.
RNAS Yeovilton is home to helicopters set to be used in Navy's mission to South China Sea
RNAS Yeovilton is a Royal Navy airfield base in Somerset, which is also used by the British Army.
It is home to the Royal Navy Commandos Helicopter force and a number of Merlin and Wildcat helicopters.
Both types of helicopters will take part in the Royal Navy's Aircraft Carrier Strike Group's mission to the South China Sea this summer.
The deployment is the first of the Navy's new £3billion aircraft HMS Queen Elizabeth.
Under current plans, HMS Queen Elizabeth will deploy in May 202.
It will be accompanied by a submarine, HMS Diamond, HMS Defender, HMS Kent and HMS Richmond supported by RFA Fort Victoria and a Tide-class tanker.
Though final numbers are yet to be decided, the group will also have eight UK and six United States Marine Corps F-35 jets, as well as nine Merlins Mk2s of the 820 Squadron based at RNAS Culdrose in Cornwall.
There will also be an unspecified number of Wildcat helicopters - which are based at Yeovilton.