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LONDON — One of Britain's most infamous radical preachers is facing up to a decade behind bars after he was convicted of encouraging support for ISIS, officials said Tuesday.

Anjem Choudary has for years been a notorious extremist cleric in the U.K. He was charged last year after appearing in a series of YouTube lectures in which he pledged allegiance to ISIS and encouraged others to support it, according to police.

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The 49-year-old, who lives in east London, was found guilty of having "invited support for a [banned] terrorist organisation" at London's Old Bailey court on July 28. The verdict was only made public Tuesday after reporting restrictions around the trial were lifted.

Anjem Choudary speaks at a rally outside London's Regents Park mosque in April 2015. ANDY RAIN / EPA

Also found guilty of the same offense was 33-year-old co-defendant Mohammed Mizanur Rahman of north London.

The pair "are believed to have been recruiters and radicalizers for over 20 years," London's Metropolitan Police said in a statement after the verdict was made public.

Choudary made headlines last year after blaming the U.S. for radicalizing "Jihadi John," the masked executioner seen in propaganda videos of ISIS beheadings.

He and Rahman were closely associated with another banned Islamist group, Al Muhajiroun — known as ALM — according to the statement. This organization, according police, was believed to be the "driving force" behind a number of people involved in several terror attacks — including the coordinated suicide bombings in London that killed 52 people on July 7, 2005, and the murder of British soldier Lee Rigby.

Despite these links, the defendants managed to stay "just within the law for many years" Commander Dean Haydon, head of the Met's Counter Terrorism Command, said in the statement.

"There is no one within the counter terrorism world that has any doubts of the influence that they have had, the hate they have spread and the people that they have encouraged to join terrorist organisations," he said. "Over and over again we have seen people on trial for the most serious offences who have attended lectures or speeches given by these men."

The investigation involved police analyzing 333 electronic devices — such as laptops and phones — which contained around 12.1 terabytes of data.

Choudary will be sentenced in September and faces a maximum sentence of 10 years in prison.