Followers of British hate preacher Anjem Choudary face new restrictions on their daily lives to prevent copycat terrorist attacks of Friday’s double murder by an unreformed extremist freed early from prison. Two convicted terrorists have already been recalled to prison after Boris Johnson announced at the weekend that the cases of 74 former inmates would be re-examined by authorities following the knife attack near London Bridge by terrorist Usman Khan. Khan, a follower of Choudary, was freed from jail in December last year after serving eight years of a 16-year sentence for plotting an Al Qaeda-inspired attack on the London Stock Exchange. Friday’s attack sparked a political row over the effectiveness and funding for prison programmes aimed at deradicalising inmates. Many of those released have been subject of a string of conditions including daytime curfews, limits on phone and internet use and bans on contacts with other extremists. They included Yahya Rashid – who was jailed in 2015 for trying to join ISIS in Syria – but was returned to prison after police found he had an undisclosed telephone. Nazam Hussain, who was convicted alongside Khan over the Stock Exchange plot in 2012, was detained by police on Sunday after a search of his house. Further detentions are expected. Breaches of the terms of release conditions could see released terrorists serve the remainder of their sentences behind bars. Criminal justice sources suggest that the already draconian monitoring measures means that that scope for further restrictions are limited. Further restrictions could also lead to future legal challenges. “The room for manoeuvre is very limited for the authorities,” said Harry Fletcher, a criminal justice expert. “They are already subject to very stringent licence conditions. The main thing they could add would be to receive unannounced police visits to check on them.” Those released from prison include other members of the so-called “Nine Lions” group who along with Usman were seeking to bomb the Stock Exchange and set up a training camp in Pakistan. A photograph published on Monday showed Khan next to Choudary at a sharia law conference in 2009 organised by the now-banned Al Muhajiroun group that was once headed by Choudary. Following the convictions in 2012, Choudary said: “From what I knew of these young chaps, they were very decent young men.” Dr Paul Stott, research fellow at the Henry Jackson Society, said many of those freed half-way through their sentences were “architects” of two decades of significant plots in Britain. “As the London Bridge attack demonstrates, they remain potentially dangerous to the public and it is imperative that the ongoing risk that they pose is assessed and, where necessary, individuals are recalled to prison,” he said. Legal sources suggested that a “knee-jerk reaction” from the government was expected with little more than a week before national elections. But the father of Jack Merritt, one of victims of the London Bridge attack, said his son would have been angered by the political reaction to the attack. Mr Merritt, 25, was a coordinator for a prisoner rehabilitation programme that had worked with Khan while he was in prison. Khan, 28, launched his attack from a conference on Friday run by the Cambridge University-run project.