Usman Khan
Darryn Frost took on the killer despite thinking he was wearing a suicide vest.
The PM reiterated his belief that it was "wrong" for convicted terrorist Khan to have been released automatically after eight years in prison.
It has also been announced that one of the three people injured during the attack was a member of university staff.
His father confirmed the news, describing his son as 'a beautiful spirit who always took the side of the underdog'.
Another man, armed only with a fire extinguisher, was also seen chasing the attacker from the scene.
The 28-year-old from Staffordshire had been imprisoned in 2012 after plotting to bomb the London Stock Exchange.