Boris Johnson has sought to blame Labour for the early release of the convicted terrorist who killed two people at London Bridge.
The Prime Minister said Usman Khan, who was freed halfway through a 16-year jail sentence, was on the streets because of laws introduced by a "leftie government".
He described the release of criminals who are "as dangerous as this man" as "repulsive" and vowed to take steps to ensure people are not released early when they commit serious offences.
But Labour leader Jeremy Corbyn said convicted terrorists should "not necessarily" serve their full prison sentence while shadow attorney general Shami Chakrabarti claimed it was "unedifying" to talk about "throwing away the keys".
Khan fatally stabbed 25-year-old Jack Merritt and another person who is yet to be named at a Cambridge University conference on prisoner rehabilitation.
The attack on Friday afternoon left three other people injured.
Khan was shot dead by police after members of the public restrained him.
Dr David Lowe , a leading expert in law and crime at Leeds Beckett University and an experienced researcher and expert in terrorism and security, said: "Politics needs to be taken out of this. Let's take the blame out of this politically.
"We need to look at the processes and laws that have been all been in place since 2010 so under the Conservatives and Liberal Democrat coalition and under the Conservatives leadership
"We also have to look at prisoner's psychological profiles. We do have to release them at some time except those that pose a great threat. It's understandable that following Friday's attack that it should be reviewed. Politicians need to stop blaming each other and deal with the incident - that is what people want. They don't want a name-calling episode.
"We need to remember that two innocent people have lost their lives and there is still another person critically injured. There are the others who are still injured as well as those that witnessed the enormity of what happened. We have to remember all those individuals and considerate of them."
After starting his career at the Foreign and Commonwealth Office, Dr Lowe worked as a police officer at Merseyside Police for 27 years before studying and teaching at Liverpool John Moores University.
He has also worked with the Home Office’s Counter Extremism unit and the Metropolitan Police’s Counter Terrorism unit.
Dr Lowe said: "In my experience as a police officer and then in terrorism and security issues such as prisoners having parole go back to the 1960s, I remember when Moors murderer Myra Hindley was repeatedly trying to get parole. There will always be individuals that are too much of a threat for parole.
"Now, we need to look at convicted terrorists and see whether they are actively planning attacks or downloading extremist material. How deeply viewed are they? And will they continue to pose a treat? Some won't and will be able to be released.
"My view is that we all need to work together for a much better approach."