The man arrested close to Downing Street in London last month while carrying several knives has been charged with preparing terrorist acts, Scotland Yard announced on Tuesday.
Khalid Mohammed Omar Ali, 27, has been charged with three offences over the incident last month, prosecutors said.
The Daily Telegraph reported said it was understood the man’s family had become concerned about his behaviour and reported him to the authorities several weeks ago.
The man was carrying a rucksack containing at least three knives when he was detained yards from the scene of last month’s terror attack by Khalid Masood.
The Metropolitan Police said the man was arrested “following a stop and search as part of an ongoing operation”.