A University of Cambridge graduate who was killed in the London Bridge terror attack has been described as a "beautiful spirit".
Jack Merritt, 25, was a course coordinator at Learning Together, which organised the prison rehabilitation conference attended by Usman Khan before his deadly rampage on Friday afternoon.
Khan, armed with two knives and wearing a fake suicide vest, killed Mr Merritt and a woman - who has not been named - while injuring three other people before being shot dead by police.
It has emerged the 28-year-old was a convicted terrorist who was wearing an electronic tag after being released half-way through a 16-year prison sentence for plotting to bomb the London Stock Exchange.
Sky News understands he was a student and personal friend of the Islamist extremist Anjem Choudary.
The licence conditions of every terrorist offender are being reviewed.
A Ministry of Justice spokesperson said: "Work is already advanced on reviewing the licence conditions of every terrorist offender, making sure conditions are as tough as they need to be.
"We are also stepping up our already frequent meetings with these offenders."
Islamic State has said one of its fighters carried out Friday's attack but the terror group has not provided any evidence. The claim is currently not thought to be credible, a security source has said.
Mr Merritt's father paid tribute to his son, who studied law at the University of Manchester before attending the University of Cambridge from 2016 to 2017.
David Merritt posted on Twitter: "My son, Jack, who was killed in this attack, would not wish his death to be used as the pretext for more draconian sentences or for detaining people unnecessarily.
"R.I.P. Jack: you were a beautiful spirit who always took the side of the underdog."
He added: "Jack lived his beliefs He held me to a high standard; he would have expected me to say this, and would have pulled me up had I not!
"He was an exceptional young man, and I'm only finding out the half of it now he's gone."
"I don't feel inspirational, but Jack was," he added.
In a statement on Saturday, Met Police Assistant Commissioner Neil Basu said there was "no evidence to suggest anybody else was involved in this attack".
He added that Khan was subject to an "extensive list of licence conditions" on his release from prison and that "to the best of my knowledge he was complying with those conditions".
Police have been searching a three-storey block of flats in Wolverhampton Road in Stafford, where Khan is believed to have been staying, and another property in Stoke-on-Trent, where had also been based.
Meanwhile, the condition of a person who was critically injured in the attack has now improved, NHS chief executive Simon Stevens said.
Three people remain in hospital - two of which are stable and a third who has less serious injuries.
Khan reportedly threatened to blow up Fishmongers' Hall while wearing his fake suicide vest before he began stabbing people shortly before 2pm on Friday.
Khan is reported to have started "lashing out" in a downstairs room of the hall but was grabbed by people at the conference and bundled out of the front door as he tried to go upstairs.
He was tackled by several members of the public - including ex-offenders and an off-duty plain-clothed police officer - before he was shot dead by police on London Bridge.
Footage posted online showed Khan being taken to the ground as one man sprays him with a fire extinguisher and another, reportedly a Polish chef, lunges towards him with a narwhal tusk believed to have been taken from the wall inside the hall.
British Transport Police confirmed one its off-duty officers helped tackle the attacker and was seen holding a knife and walking away from the scene.
Chief Constable Paul Crowther said: "The courageous actions he took when faced with the horrors of this attack are remarkable. He, as well as other members of the public, should be extremely proud of what they did to stop this man on London Bridge."
Khan was handed an open-ended indeterminate sentence in February 2012 for public protection over his part in an al Qaeda-inspired terror group that plotted to bomb the London Stock Exchange.
He had also planned build a terrorist training camp on land in Pakistan-controlled Kashmir owned by his family.
A list of other potential targets included the names and addresses of the Dean of St Paul's Cathedral in London, then London mayor Mr Johnson, two rabbis, and the American Embassy in London.
However, the sentence for Khan - along with two co-conspirators - was quashed at the Court of Appeal in April 2013.
He was instead given a determinate 16-year jail term before being freed on licence in December last year and made to wear the tag.
The Parole Board said it had no involvement in his release and that Khan "appears to have been released automatically on licence (as required by law), without ever being referred to the board".
During his prison sentence, Khan asked to take part in a deradicalisation course to become a "good British citizen", claiming he was "immature" when he committed the offence, according a letter he wrote that has been obtained by ITV News.
Prime Minister Boris Johnson, who visited the scene of the attack on Saturday with Home Secretary Priti Patel and Metropolitan Police Commissioner Cressida Dick, said he has "long argued" that it is a "mistake to allow serious and violent criminals to come out of prison early".
He said: "It does not make sense for us as a society to be putting people convicted of terrorist offences, of serious violent offences, out on early release."
The Queen and Duke of Edinburgh sent a message of sympathy to those killed and affected by the "terrible violence" and praised the "brave individuals who put their own lives at risk to selflessly help and protect others".
The attack came weeks after the UK's terrorism threat level was downgraded to "substantial" from "severe", meaning attacks were thought to be "likely" rather than "highly likely".
Home Secretary Priti Patel made the announcement on 4 November - days after parliament voted to hold an early election.
London Bridge was the scene of a terror attack in 2017 - also during a general election campaign - when eight victims were killed along with the three terrorists, who were also wearing fake suicide vests and armed with knives.