The conviction of Anjem Choudary shows that new counter-extremism powers are unnecessary, free speech campaigners have said.
The Defend Free Speech campaign – backed by The Christian Institute – said the ruling against Choudary makes it clear that existing legislation is sufficient to target genuine extremists.
The campaigners are opposed to planned Extremism Disruption Orders which they say will stifle free speech and hit those who simply hold traditional views.
Choudary was found guilty of inviting support for the banned group calling itself Islamic State, under section 12 of the Terrorism Act 2000.
The Campaign Director of Defend Free Speech, Simon Calvert, said: “What we have seen with the conviction of this dangerous individual is that existing legislation can be used effectively to target those who incite others to join terrorist organisations and take up arms against their country.”
Mr Calvert stated that the case does not show why the Government needs a broad law that could “potentially criminalise many ordinary people who hold traditional or strong views”.
He added that the Government’s argument for its law is unravelling, with a series of problems making the case for “ditching this policy altogether”.
“The complete absence of safeguards, the lack of a clear definition of what is deemed to be extreme, and a plethora of legislation that can already be used against those inciting hatred, promoting violence or encouraging terrorism” show why the plans should be dropped, he said.
Mr Calvert noted: “No wonder both the current and previous independent reviewers of terrorism, David Anderson and Lord Carlile, have voiced their concerns about these plans.”
Influential political website ConservativeHome also questioned the Government’s extremism plans in the light of Choudary’s conviction.
Editor Paul Goodman said “a workable definition of extremism seems to be a contradiction in terms”.
He added that Prime Minister Theresa May should be encouraged to drop that aspect of the upcoming extremism Bill, “if not the whole measure”.
Last month, MPs and Peers warned that the plans could indiscriminately penalise religious conservatives.
In a strongly-worded report, the Joint Committee on Human Rights said the Government had offered “no impression of having a coherent or sufficiently precise definition of either ‘non-violent extremism’ or ‘British values'”.
Without a clear definition, the Committee said, authorities would have “wide discretion to prohibit loosely defined speech which they find unacceptable”.