An intruder wielding a crossbow who scaled a fence at Windsor Castle and threatened to kill Queen Elizabeth II on Christmas Day in 2021 pleaded guilty on Friday to treason, the first person to be convicted of such a charge in Britain in more than four decades.
The episode occurred during the depths of the coronavirus pandemic, when the queen was sequestered at Windsor Castle, and drew disquieting comparisons to an even more serious breach in 1982, when a man broke into Buckingham Palace and entered her bedroom before being arrested.
In the Christmas Day incident, the intruder, Jaswant Singh Chail, 21, of Southampton, was confronted by the police at a gate that led to the queen’s private quarters in the castle. Asked what he was doing there, he twice responded, “I am here to kill the queen.”
The queen died of natural causes in September at Balmoral Castle in Scotland at 96, having survived a bout with Covid-19. She faced infrequent security threats during her 70-year reign, most famously in the 1982 episode, when the intruder, Michael Fagan, wandered the palace undisturbed before finding his way to Elizabeth’s bedroom and waking her up. She quickly called for help.
A year earlier, a man fired six blank shots at the queen as she rode past on horseback during a parade on her birthday in London. That man, Marcus Sarjeant, was charged and convicted under the Treason Act.
The Metropolitan Police said that two officers spotted Mr. Chail, clad in black and wearing a metal mask, on the castle grounds at 8:10 on Christmas morning. One of the officers drew a Taser as they approached him. The officers discovered that Mr. Chail was carrying a crossbow, loaded with a bolt with the safety catch off.
The intrusion prompted the government to review regulations on the purchase of crossbows. Under existing laws, crossbows can be purchased over the counter or on the internet by those over the age of 18.
“This was an extremely serious incident, but one which the patrolling officers who apprehended Chail managed with great composure and professionalism,” Richard Smith, commander of the counterterrorism unit of the Metropolitan Police, said in a statement.
“They showed tremendous bravery to confront a masked man who was armed with a loaded crossbow, and then detain him without anyone coming to harm,” he added.
Mr. Chail, who has been detained at Broadmoor Hospital in Crowthorne, about 30 miles west of London, posted a video on social media before he set off for Windsor, saying that he planned to kill the queen.
He said he was acting to take revenge for the treatment of South Asians, citing the 1919 massacre in Amritsar, India, during which British troops fired on pro-independence demonstrators.
In addition to treason, Mr. Chail pleaded guilty to threatening to kill a person and to possessing a deadly weapon. He is scheduled to be sentenced on March 31. Back in the 1980s, Mr. Sarjeant was sentenced to five years in prison for his attack.