Despite the conviction of hate preacher Anjem Choudary, his followers are still posting online videos promoting Islamic extremism.
They include calls to arms to fight the non-believers, the glorification of Islamic State atrocities, and demands for a world governed by Sharia law, The Times reports.
The British-born 49-year-old encouraged backing for Isis in a series of talks posted on YouTube, and recognised a caliphate - a symbolic Islamic state - had been created under an IS leader after it was announced on June 29 2014, the Old Bailey heard.
Last month Choudary and co-defendant Mohammed Mizanur Rahman, 33, were found guilty of inviting support for IS between June 29 2014 and March 6 2015.
Some of the videos still available online contain speeches from Siddhartha Dhar who travelled to Syria. In one he labelled Jewish people as corrupt and arrogant, while publicising Nazi propaganda.
Counter-terrorism experts told the newspaper the posts were alarming because Choudary was so successful in using the internet to spread his message.
Until reporting of his conviction was allowed on Tuesday, it appeared that little action was taken by internet companies in relation to his activity.
But his official account is no longer visible. Choudary amassed 32,000 followers and his Old Bailey trial heard how British authorities tried and failed to get his posts taken down in August last year and the following March.
Richard Walton, former head of counter-terrorism at Scotland Yard, told The Times: “There should be some way of restricting behaviour that is not necessarily criminal but is clearly on the cusp, is grossly antisocial and grossly offensive.
“And particularly where we know it is politically motivated as well, in support of groups like Islamic State.”