Security minister Ben Wallace has called for the public to report 'odd behaviour' in an attempt to stop future terror attacks.
The Wyre and Preston North MP warned that as attackers use "everyday items" such as knives and cars to strike a "free and open" society, individuals, community leaders and car hire businesses among others should "get ahead of the game".
Mr Wallace also suggested that terrorists were driven to pick "nearby" items - as instructed by terrorist grooming materials, he said - because of the difficulty in obtaining guns as a result of police and Government efforts.
His calls came hours after a 29-year-old man struck a barrier outside the Houses of Parliament at around 7.40am on Tuesday using a silver Ford Fiesta.
The British national, who was arrested on suspicion of preparing an act of terror, left a number of people injured after crashing into cyclists.
Mr Wallace told the Press Association: "These type of attacks use cars, they use knives - everyday items to attack us when we're at our most vulnerable.
"In crowded spaces, when we're going about our normal jobs, going to work, and they do that because they know that that's where in our society - in a free and open society - we are vulnerable.
"We need to think about people behaving badly. If we see odd behaviour we need to report it to the police, we need to report it to the local authorities, report it to our community leaders."
"It's also why we need to work with the private sector like car hire companies to say, 'Are you suspicious', 'Why is this person who's never driven an HGV hiring an HGV'."
Security measures around Westminster and central London have been stepped up following a string of attacks on some of the capital's busiest landmarks last year.
Barriers were put up on bridges including Westminster, Waterloo and Lambeth to stop terrorists mowing down pedestrians.
It came after Khalid Masood drove a hired SUV into pedestrians on Westminster Bridge in March 2017 before fatally stabbing Pc Keith Palmer outside the Palace of Westminster.
Khalid Ali was arrested in Parliament Square around a month later armed with three knives.
Armed policing received a boost with a £143 million investment soon after the Paris attacks in November 2015.
Mr Wallace thanked the emergency services and added that the lessons learned from last year's attacks are vital in helping to protect "iconic buildings" which he said reflect a way of life that "both far-right and Islamist terrorists hate".
He said: "We can go right back to the IRA days - that's how we have learnt in this great capital to deal with terrorism, it's why Londoners have gone back to work pretty quickly, they haven't let this disrupt their life today.
"All those things are because we import the lessons and we continue to fine tune."