London(CNN) British Islamist preacher Anjem Choudary has been released from prison.

The 51-year-old self-styled cleric, jailed in 2016 for inviting support for ISIS, was let out of the high-security Belmarsh prison in southeast London on Friday morning.

A former solicitor, he had previously stayed on the right side of the law for years and was popular with British television networks.

He was due for automatic release halfway through his five-and-a-half-year sentence, when time served is taken into account.

He will be subject to a strict supervision regime, and has been taken to a probation hostel instead of going home to his wife and family in the east London suburb of Ilford.

Police and the MI5 security service are expected to be among a host of agencies involved in monitoring him in the community.

He will also be subject to a package of restrictions including the obligation to have all travel plans approved, electronic tagging, a nighttime curfew and a requirement to stay within a set area.

He will be able to attend only certain mosques and will be banned from contacting individuals who are known or believed to have been charged with or convicted of extremist-related offenses without prior approval.

Choudary, who used his Twitter handle to gain attention, will also be banned from social media.

His name has been added to a United Nations sanctions list, which means he is subject to an assets freeze and travel ban.

Controversial figure

Choudary has courted controversy over two decades, skirting the edges of the law, backing extremism but with no proof of actually inciting violence. He earned the wrath of Britain's tabloid newspapers, making him -- by his own admission -- the country's "most hated man."

In 2014, he pledged allegiance to ISIS and its leader Abu Bakr al-Baghdadi, bringing him under scrutiny and leading to his arrest.

British authorities say Choudary has been linked to the radicalization of a string of terrorists who have stood trial in the UK over the past 15 years.

He is the co-founder of the now-outlawed radical Islamist organization Al-Muhajiroun.

He was pictured at a protest with Michael Adebolajo, later convicted of the violent murder of British soldier Lee Rigby, and he was linked to Siddhartha Dhar, suspected by authorities of replacing Mohammed Emwazi, or "Jihadi John," as ISIS executioner.

But rather than traveling to Syria himself, Choudary has stayed in Britain -- where he was born and raised -- and taken on the role of a vocal supporter of ISIS and radical Islam.