According to the statement, a crossbow was recovered after a search for the intruder.
“The man was taken into custody and has undergone a mental health assessment – he has since been classified under the Mental Health Act and remains under the care of medical professionals,” police said.
“The investigation into the full circumstances of this incident is being conducted by Metropolitan Police Specialist Operations,” the statement added.
The man did not enter any buildings, officials said.
The 95-year-old Queen celebrated Christmas at Windsor Castle after making the decision not to travel to Sandringham, her usual Christmas destination, due to the pandemic. She was joined at Windsor by her son, Prince Charles, and Camilla, the Duchess of Cornwall.
Although it is not common, break-ins into royal palaces do occasionally happen. Perhaps the most famous incident dates back to 1982 when a man named Michael Fagan, who was then 31, climbed a wall of Buckingham Palace, crawled through an open window and made his way into Queen Elizabeth II’s bedroom, who was asleep. .
The Queen was unharmed, although the break-in raised serious questions about the palace’s security, especially when her repeated attempts to call for help were found to have been ignored.