One person died and eight people were wounded, two seriously, after the vehicle rammed into people leaving Ramadan prayers in Finsbury Park, north London, in the early hours of Monday morning.
Imam Mohammed Mahmoud, of the Muslim Welfare House, has been hailed a hero for stepping in to protect the suspected attacker, a 48-year-old man, telling the furious mob: "Do not touch him."
Eyewitnesses told CNN that they saw a group of bystanders drag the driver out of the white van, pin him to the ground and hit him.
Toufik Kacimi, CEO of the Muslim Welfare House, a community center and mosque near the scene, told CNN that the imam "went quickly and grabbed the guy because the people there were trying to hit and kick the guy, but he saved him, and kept him safe until the police arrived."
Witness Hussain Ali, 28, told the Press Association that "the leader of the mosque said 'You do not touch him'. He was sitting and holding him like that, people kept holding him."
Mahmoud's actions in shielding the driver are said to have quietened a potentially dangerous situation, and helped save lives.
Speaking to the media later on Monday, the imam downplayed his actions, insisting that he had not acted alone.
"There were a group of brothers who were calm and collected and managed to calm people down and to extinguish any flames of anger or mob rule that would have taken charge had this group of mature brothers not stepped in," he said.
Mahmoud said he was in the mosque shortly after prayers when "a brother came in, quite panicked, and said that somebody had run over a group of people and tried to kill them so we rushed out."
"We found about 15 to 20 people on the scene tending to the injured, administering CPR on the brother who is now deceased, and three people restraining the assailant," he said, adding "they couldn't hold him down and push back the people trying to hit him, so we pushed those people back."
The Mayor of London, Sadiq Khan, told Sky News earlier on Monday that the imam's actions in "calming things down" were "what I'd expect from a good faith leader, from a good Muslim leader."
Deputy Assistant Commissioner Neil Basu, senior national coordinator for counter-terrorism policing, told reporters at Scotland Yard he wanted to praise the members of the public who helped in the immediate aftermath: "Their restraint in the circumstances is commendable."
Mahmoud said he feared the attacker's words and actions were "maybe proof that this demonization of the Muslim community at the hands of those who ... wish to divide this country and divide this great city has succeeded to some extent, in influencing the vulnerable and the impressionable into thinking that we're barbaric and that we are people who like to shed blood and that therefore we must be exterminated."
But he insisted: "This community of ours in Finsbury Park is mild-mannered, calm ... not known for violence. Our mosques are incredibly peaceful. Immediately after the incident, people were praying for the victims of the attack." Mahmoud said he hoped that people would continue to unite against extremism.