A man who climbed over a wall and got into the grounds of Buckingham Palace while Queen Elizabeth II was at home is a convicted murderer, authorities said.
Dennis Hennessy pleaded guilty to trespass at a court appearance Friday.
He was arrested in the palace grounds on Wednesday evening. Police say he was not armed.
Prosecutor Tom Nicholson told the court that 41-year-old Hennessy walked around the gardens for about 10 minutes toward the palace before being arrested. As he was detained he asked "is Ma'am in?" — the courtesy term used for the queen.
Prosecutors said Hennessy was on parole after being convicted of the murder of a homeless man in 1992.
The queen was at the palace Wednesday after attending the State Opening of Parliament.
Several intruders have breached security at the queen's London residence over the years — including a naked paraglider who landed on the roof in 1994.
In 2013, two men were arrested on suspicion of burglary — one in the grounds and one inside an area of the palace that's open to the public during the day.
In 1982, an unemployed man named Michael Fagan managed to climb up a drainpipe and sneak into the queen's private chambers while she was still in bed. Elizabeth spent 10 minutes chatting with the intruder before calling for help when he asked for a cigarette.