Government ministers are considering a raft of measures to crack down on hate preaching in the wake of the jailing of Anjem Choudary, who was allowed to promote Sharia in the UK for two decades.

Questions have been raised over how Choudary was able to spread his message of hate for so long without falling foul of the law, influencing thousands of people during that time.

In recent years he urged his followers to pledge allegiance to, and travel to Islamic State in Syria, describing it as an “obligation” for devout Muslims. Security services estimate that Choudary has links to more than 500 extremists who left the UK to join Islamic State, and as many as 15 separate terror plots organised in the last 16 years.

Parliamentarians have already called for a tightening of the laws surrounding social media after it emerged that both YouTube and Twitter refused police requests to remove content posted by Choudary designed to radicalise his followers.

The government is limited in its scope for legislating in this area as the social media companies are based abroad, and therefore outside of British jurisdiction. However, they are investigating measures which could give the security services more powers to order the removal of online content or accounts.

Ministers are now also hinting that they will look at bans on known hate preachers from entering certain mosques, universities, and community groups, as well as a restriction on the number of people radical preachers can address in public at a time, the Telegraph has reported.

The measures, which go much further than anything considered by the government under former Prime Minister David Cameron, could comprise the core of a new Extremism Bill to be placed before Parliament next May. It is understood that current Prime Minister Theresa May sees countering extremism as one of her “top priorities,” and has already held a number of meetings on the subject.

David Anderson, the Government’s Independent Reviewer of Terrorism Legislation, has called for ministers to tighten anti-terror laws to prevent others preaching hate.

Speaking on BBC Radio 4’s Today programme, he said of current anti-terror measures: “These are useful offences, they are being increasingly used, but I think one would have to admit that until now the law has barely touched Anjem Choudary.

“In the meantime a lot of people have been radicalised and yes, we do need to look at what might be done if there are impediments, technical reasons why it’s not as easy to get convictions under these laws as it should be.”

Choudary’s conviction came after a two-year-long investigation by Scotland Yard, at a cost of millions of pounds.

However, Mr Anderson raised concerns over measures which would apply restrictions on suspects without court approval, which he argued would be “very dangerous” and could be “counterproductive”.

Labour MP Keith Vaz, who chairs the Home Affairs Committee, said “While congratulating the police in bringing this case to a successful conclusion we now need to look again at the law to ensure that it allows no gaps that permit preachers of hate to undertake their activities under the cloak of freedom of speech exercised in a democracy.

“In future we need to show zero tolerance to those who act and behave in this way.”

Follow Donna Rachel Edmunds on Twitter: or e-mail to: dedmunds@breitbart.com//