LONDON (AP) — The British Army said Tuesday it has launched an urgent investigation after an intruder posing as a priest reportedly spent the night at the barracks of troops who guard Queen Elizabeth II at Windsor Castle.

The Sun newspaper and broadcaster Talk TV reported that the man was admitted to Victoria Barracks last week after claiming to be a friend of the battalion’s padre. It said he spent the evening eating and drinking with senior officers before being offered a bed for the night, despite showing no identification or credentials.

Police were summoned the following morning and the man was removed. He was not arrested.

The barracks is close to the castle, 30 miles (50 kilometers) west of London, where the queen spends much of her time. The 96-year-old monarch was staying at her Sandringham estate in eastern England when the alleged intrusion took place.

The barracks is home to the Coldstream Guards, who stand guard outside the palace in their distinctive red jackets and bearskin hats. Thousands of tourists are expected in Windsor next month as the U.K. celebrates the Platinum Jubilee, marking the queen’s 70 years on the throne.

The army said in a statement that it “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.”