The families of the two people killed in London on Friday (November 29) have released heartfelt tributes. Saskia Jones and Jack Merritt were fatally stabbed in an attack on London bridge. They were involved in a prisoner rehabilitation conference - which their attacker had also been attending. The family of Jones said the twenty-three-year-old had a 'wonderful thirst for knowledge' and a 'great passion for providing invaluable support to victims of criminal injustice.' Merritt's family described him as 'thoughtful and empathetic' while working towards helping people in the criminal justice system. They also said the twenty-five-year-old would not want the attack 'to be used as a pretext by the government for introducing even more draconian sentences on prisoners, or for detaining people in prison for longer than necessary'. The attacker - identified as Usman Khan - had been convicted of terrorism in 2012 but was let out early. British Prime Minister Boris Johnson said on Sunday (December 1), he would strengthen prison sentences and boost security in the wake of Friday's attack. Johnson called it a terrorist act.