The Queen is said to have been hit by a security breach after a stalker was found just metres away from Windsor Castle.
According to The Sun, the intruder posed as priest and a friend of the padre to the Coldstream Guards where soldiers allowed him in to Victoria Barracks despite not having shown any ID.
The Barracks is located just 250 metres from Windsor Castle with a source close to the Royal Family reportedly telling The Sun it was an "extraordinary breach of security."
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According to The Sun the source added: “The guy turned up at the gate in the evening and said his name was Father Cruise and claimed to be a friend of the battalion's Padre Rev Matt Coles. He was invited in and offered something to eat in the Officer’s Mess.
“Within a couple of hours, he was drinking with the officers in the bar and telling them stories of how he had served in Iraq. He was telling lots of tall stories and the lads were enjoying his banter and having a few drinks.
“It was only later in the evening when he started talking about how he had worked as an ejector-seat test pilot and had donated some of his organs that the chaps started to get suspicious.
“But in any event he was allowed a bed for the night. Checks were made in the morning and it was apparent this guy wasn’t a bona fide priest and the police were called.”
After the alarm was raised the following morning, police were said to have escorted the man from the premises a few hours before the Queen returned to Windsor having just spent Easter at Sandringham.
A Thames Valley Police spokesman said: “We received a report of an intruder at Victoria Barracks in Sheet Street, Windsor, at 9.20am on Wednesday.
“Officers attended and removed the intruder from the barracks. No further action was required.”
In response to the incident, the Ministry of Defence told the Daily Star the incident would be investigated 'as a matter of priority.'
As reported by the Daily Record, an Army spokesperson said: “The Army takes this breach of security extremely seriously and it will be thoroughly investigated as a matter of priority.
“This incident is now part of an ongoing investigation and it would therefore be inappropriate to comment further at this time.”
A spokesman for the Royal Family informed the Daily Star they would not be commenting on the story.