It is third time a person has tried to enter Buckingham Palace grounds this year.
A man was arrested on Friday for allegedly climbing over a gate at Buckingham Palace in London.
The 21-year-old was arrested by security officers for trespassing a designated site in the palace as he dropped to the ground, Scotland Yard said.
The accused was not carrying any offencive weapon but investigations are continuing, the BBC reported.
He has been taken into custody and will undergo a mental health assessment. No members of the Royal Family are thought to have been at the palace at that time.
It is third time a person has tried to enter the palace grounds this year.
A 22-year-old man was spotted on CCTV in August after climbing over a security fence but he was stopped "within a security perimeter".
Several months earlier, a 41-year-old man spent seven minutes in the grounds before being arrested.