In 2016, British authorities sentenced pro-ISIS propagandist Anjem Choudary to five-and-a-half years in prison for his public declarations in support of the terror group. Choudary previously led the now-banned British group al-Muhajiroun, which included several notable extremists among its membership and was outlawed in the United Kingdom for its links to terrorism.

Choudary is expected to walk free this month after serving only half of his sentence. The bewildering reason is British probationary law, which blanketly allows prisoners with fixed-term (non-life) sentences to be released on probation after completing 50 percent of their sentences.

Police arrested Choudary, Mohammed Mizanur Rahman, and several others in 2014 for public support of ISIS after Choudary pledged allegiance to ISIS and encouraged others to do the same. Even beyond his support for ISIS, Choudary has been linked to more than 600 extremists and, through them, dozens of terror plots, including the 2017 London Bridge attack and the 2013 murder of British soldier Lee Rigby.

Among the hundreds of extremists to whom Choudary is linked are:

• Abu Rumaysah (Siddhartha Dhar): A Choudary associate who was arrested alongside the preacher in 2014 for encouraging terrorism. He fled for Syria while out on bail and his whereabouts are currently unknown.
• Khuram Butt: One of the June 2017 London Bridge attackers who belonged to Choudary’s al-Muhajiroun organization.
• Michael Adebolajo: One of two murderers of British fusilier Lee Rigby. He reportedly attended al-Muhajiroun events. Adebolajo was sentenced to life in prison.
• Michael Adebowale: One of two murderers of British fusilier Lee Rigby. He reportedly attended al-Muhajiroun events. Adebowale was sentenced to 45 years in prison.
• Mohammed Mizanur Rahman: Rahman was arrested alongside Choudary in 2014 and also sentenced to five-and-half years in prison. Rahman is also expected to be released by the end of 2018, and some authorities have warned that he is more dangerous than Choudary because of his youth.
• Omar Bakri Muhammed: The Syrian Islamist cleric who created the al-Muhajiroun network in the United Kingdom and recruited Choudary. He is currently serving a prison sentence in Lebanon for organizing jihadist training camps there.
• Ubaydullah Hussain: A Norwegian-Pakistani national and incarcerated ISIS supporter. Hussain visited Choudary in England in 2014 just three months before Choudary’s arrest.

Terror plots to which Choudary is linked include:

• A 2018 failed car ramming plot by former al-Muhajiroun member Lewis Ludlow
• The May 3, 2015, attack on a “Draw Muhammad” contest in Garland, Texas. After the attack, Choudary publicly told contest organizer Pamela Gellar she should have anticipated a violent response.
• A 2012 failed plot to blow up the London stock exchange. Four of the perpetrators were former students of Choudary’s. He reportedly claimed the plans were “taken out of context.”
• A 2012 failed terror plot by al-Muhajiroun member Mohammed Benares, who was arrested that March for downloading al-Qaeda bomb-making plans. He was found guilty and jailed the following year.

British authorities say they will take steps to prevent Choudary’s resumption of his cheerleading for ISIS and terror. Officials have announced more than 20 restrictions they intend to place on Choudary, including barring him from Internet access or meeting with former al-Muhajiroun colleagues, including Rahman. Additionally, MI5 has pledged it will keep close surveillance on Choudary.

The British Parliament last month began discussing the Counter-Terrorism and Border Security Bill 2017-19, which would increase maximum sentences for terror offenses and curb early releases for terror convicts like Choudary. These steps are encouraging, but Choudary—a trained lawyer—is likely to control his speech and actions just enough to remain technically within the law, while continuing his advocacy for and encouragement of extremist ideologies and actions. He and his followers unfortunately pose as great a threat now as they did at the time of Choudary’s sentencing.