The man detained on suspicion of terror offences after a car crashed outside the Houses of Parliament is believed to be a British citizen of Sudanese origin, a security service source has told HuffPost UK.
Early indications suggest the 29-year-old lives in the Sparkhill district of Birmingham after gaining British citizenship, the source, who did not want to be named, said.
The man was known to the police, but did not feature on any terror or security services watch list.
On Tuesday night, there was a police presence near the Bunna Internet Cafe on Stratford Road in the city, but it was not confirmed whether that was in relation to the Westminster probe.
It appears he spent several hours in Birmingham and visited addresses there, which are now being searched for clues and possible associates.
The city has in recent years developed a reputation for being a backdrop to extremism, having been the home to an alleged Saudi financier of the 9/11 attacks, the birthplace of Britain’s first suicide bomber and the centre of the country’s first Al Qaida terror plot.
Police arrested the suspect after a Ford Fiesta crashed into cyclists and pedestrians at around 7.40am on Tuesday before smashing into a security barrier.
Three people were treated for injuries after the incident. One man was treated at the scene while a man and woman were taken to hospital with non-life threatening injuries. Both have since been discharged.
The man was alone in the car and no weapons were recovered from the vehicle. Police said in the hours after the incident that the suspect was not co-operating.
The Fiesta, registration number FL10 CWZ, was privately owned and travelled from Birmingham to London late on Monday night, arriving in the London area just after midnight this morning, Scotland Yard said.
The vehicle was in the Tottenham Court Road area from approximately 01:25 until 05:55 this morning, and was then driven around the Westminster and Whitehall area from approximately 06:00 until the incident at 07:37.
Roger Godsiff, the Labour MP for Birmingham Hall Green, said the suspect is believed to have been living in his constituency,
He said: “Today’s attack at Westminster was carried out by an individual who is believed to have been living in my constituency in Birmingham.
“My deepest sympathies to the cyclists and pedestrians who were injured in the attack.
“I have told the police and security services that they have my total support in doing whatever is necessary to protect the public in London and Birmingham.”
The Metropolitan Police said they were treating it as a terrorist incident because of the method used, the fact it appeared to have been deliberate and due to the “iconic location” where it happened.
Counter-terrorism officers also conducted searches at a residential property in Nottingham as part of the probe.
Plain-clothed police officers could be seen outside an address in Peveril Street in Nottingham on Tuesday evening, which was said by neighbours to be home to six Sudanese people.
No other arrests have been made.
Home Secretary Sajid Javid has said people “must keep an open mind” about the suspected terror attack.
Speaking at the Home Office, Javid said he was limited in what he could say as the investigation was live.
He said: “There are understandably a lot of questions about the incident and what has happened. I think people will appreciate it’s only just happened in the early hours of this morning.
“The briefing I have received from counter-terrorism police and the security services is that work is ongoing and they are doing everything they can to find out more about the incident.
“We must keep an open mind about what has happened and I’m sure when they do have more information they will say more.
“We must give the time the police need to do their work.”