There's a call for a beefing up of security at Westminster following the terror attack, which Islamic State has claimed responsibility for.
The 52-year-old was British born and had a range of previous convictions.
Anthony Glees from the University of Buckingham told Rachel Smalley there should be more intrusive surveillance, and more stopping and searching.
"The beating heart of our democracy, which is Westminster, cannot be a place that somebody with a knife can walk into and be confronted only by an unarmed policeman."
He said Westminster has a lot of police officers and CCTV and is meant to be a particularly secure area.
Glees said the attacker was on MI5's radar but was allowed to slip off it, like the 2005 London bombers.
"The answer to this is for MI5 to take all those people that they know about, who they say are 'desirable' targets but not 'essential', to move them from the 'desirable' pile into the 'essential' pile."
He said it would require more resources and more cash, but said they have to keep Britain safe.
LISTEN ABOVE AS ANTHONY GLEES SPEAKS WITH RACHEL SMALLEY
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