The terror suspect arrested with several knives in Whitehall in the Westminster area of London on Thursday is understood to be Khalid Mohammed Omar Ali.
It is thought the 27-year-old is a British national who was born overseas and went to school in Tottenham, north London.
The suspect was detained by armed officers after a stop-and-search in an “intelligence-led” operation.
He remains in custody, having been arrested on suspicion of offences under the Terrorism Acts and possession of offensive weapons.
The police swoop took place yards from the scene of last month's deadly attack by Khalid Masood in Westminster.
Reports suggest the suspect was arrested after a concerned family member contacted authorities.
Detectives are continuing to question him, while two searches are being carried out at addresses in London.
PA