An investigation into an “extraordinary breach of security” is under way after an intruder pretending to be a priest reportedly spent the night eating and drinking with soldiers at a barracks close to Windsor Castle.

Police were alerted to reports of an intruder at Victoria Barracks on Sheet Street, Windsor on Wednesday, while the Queen was at Sandringham for Easter.

The soldiers had reportedly been approached at the gate by the man, who said his name was Father Cruise. He allegedly went on to spend the night eating and drinking with senior officers despite showing no identification or credentials. The man was also offered a bed for the night.

Speaking to TalkTV, a source called the incident an “extraordinary breach of security” and said that it is believed the man “turned up at the gate in the evening … and claimed to be a friend of the battalion’s Padre Rev Matt Coles”. He was then invited in and offered food in the officer’s mess.

The source added that once inside the man drank with the officers in the bar, enjoyed “banter with the lads” and told them tall stories of how he had served in Iraq.

A spokesperson said that the incident will be “thoroughly investigated as a matter of priority” and that the army “takes this breach of security extremely seriously”. As the incident is now part of an ongoing investigation, the army stated it would be “inappropriate to comment further at this time”.

A Thames Valley police spokesperson said they received a report of an intruder at Victoria Barracks in Sheet Street, Windsor, at 9.20am on Wednesday. They confirmed that “officers attended and removed the intruder from the barracks. No further action was required.”

The barracks are home to the Coldstream Guards, who have a ceremonial role as protectors of Windsor Castle and Buckingham Palace and are known for their distinctive red jackets and black bearskin hats.