Two men have been arrested after a trespassing and burglary incident at Buckingham Palace – the official residence of the British monarch – the most serious security breaches at the building in decades.

British authorities said the shocking break-in incident took place on Monday night in which at least one man climbed a wall and kicked open a door to gain entry to the high-security palace. The man evaded at least three layers of security to make his way into the palace in what appears to be the worst breach of its security since 1982 when Michael Fagan was arrested in the Queen’s bedroom after she raised the alarm.

The palace is filled with magnificent paintings, sculpture and antique furniture. It is also the administrative centre for the British royal household. Police said the man was found “in an area currently open to the public during the day” and arrested for burglary, trespass and criminal damage.

They said a second man was arrested outside the palace for conspiracy to commit burglary following the incident. A spokesman for the Metropolitan Police said both men have now been bailed.