Anjem Choudary, Britain's most high-profile Islamist preacher whose followers have been linked to numerous militant plots across the world, has been found guilty of inviting support for the Islamic State jihadist group.
Choudary, 49, was on Tuesday convicted at London's Old Bailey court of using online lectures and messages to encourage support for the banned group which controls large parts of Syria and Iraq.
Notorious in Britain where the tabloids denounce him as a hate preacher, he is also well-known abroad, making regular TV appearances in the wake of attacks by Islamist militants to blame Western foreign policy for targeting Muslims.
"These men have stayed just within the law for many years, but 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," said Dean Haydon, head of London police's Counter Terrorism Command.
Prosecutors said that in postings on social media, Choudary and his close associate Mizanur Rahman, 33, had pledged allegiance to the "caliphate" declared by Abu Bakr al-Baghdadi and said Muslims had a duty to obey or provide support to him.
Both men, who had denied the terrorism charges and claimed the case was politically motivated, were found guilty last month but their convictions could not be reported until Tuesday for legal reasons. They are due to be sentenced in September and could face a jail sentence of up to 10 years each.
Choudary, the former head of the now banned organization al-Muhajiroun, became infamous for praising the men responsible for the 9/11 attacks on the United States and saying he wanted to convert Buckingham Palace into a mosque.
Despite his often controversial comments and refusal to condemn attacks by Islamists, such as the London 2005 bombings, Choudary has always denied any involvement in militant activity and had never been previously charged with any terrorism offence.
Al-Muhajiroun has been regarded as a breeding ground for militants since it was founded in the late 1990s by Syrian-born Islamist cleric Omar Bakri, who was banished from Britain in 2005, and was banned under anti-terrorist laws in 2010.
Police said it was suspected of being the driving force behind the London bombings while Michael Adebolajo, one of the men who hacked to death British soldier Lee Rigby on a London street in 2013, had attended protests Choudary had organised.
The group's influence is said to extend far beyond Britain.
Both Choudary and Rahman say they abide by a "covenant of security" which forbids Muslims from carrying out attacks in non-Muslim lands where their lives and wellbeing are protected.