He has since been sectioned under the Mental Health Act, the Metropolitan Police said.
The force said the incident happened at around midday on Tuesday 14th December 2021 when a vehicle tried to enter Carriage Gates at the Palace of Westminster.
It is not being treated as a terror incident, police said.
“A male inside the vehicle was detained before being sectioned under the Mental Health Act,” a Met spokesperson said.
“There was no damage to property and no injuries were sustained.”
The spokesperson confirmed no taser was used in the incident.
The car attempted to drive through the same gate where PC Keith Palmer was stabbed to death by terrorist attacker Khalid Masood while guarding parliament in 2017.
The incident on Tuesday comes just days after the UK parliament faced a “major security breach” when a man jumped over a fence to access the estate. A Met spokesperson said this intruder was arrested at Carriage Gates “on suspicion of trespassing on a protected site”.
The UK parliament has been approached for comment.