The UK's counter-extremism tsar is calling on the government to overhaul urgently its terror legislation to ensure extremists are not exploiting gaps in the law.
The head of the Commission for Countering Extremism, Sara Khan, has launched a legal review into the UK's terror laws but says the government needs to act now.
She told the BBC's Today programme that every day the government fails to act more people will become radicalised.
"Every day I see extremists spreading propaganda, from justifying and celebrating the murder of MPs, acts of suicide bombing or glorifying terrorists such as Brenton Tarrant, to people encouraging attacks on places of worship, and it is frightening material," she said.
"What concerns me is that the government's counter-extremism strategy needs a complete and urgent overhaul. It is not really dealing with this in the effective way that it requires and we need to carry out this legal review to ensure that there are no gaps in the law that extremists are exploiting and where they are, in effect, operating with virtual impunity in this country.
"I call on the government, in light of seeing extremists exploit the pandemic and the Black Lives Matter protests, that they urgently commit themselves to working on this new counter-extremism strategy and to recognise that every day we do not do that we are seeing extremists radicalise, recruit people and mainstream their propaganda. We need to act now."
The commission believes there are gaps in the law allowing extremists to "sow divisions" and are looking into whether a new law could be introduced.
It has found evidence of a number of incidents in which hateful behaviour has happened but failed to meet the threshold to be considered a crime under current laws.
When it announced its review last week it cited the actions of barred Indian preacher Zakir Naik, whose Peace TV stations have been fined for hate speeches, as an example of where the current laws fail.
Mr Naik ran two television stations, Peace TV and Peace TV Urdu, which were fined £300,000 last month by the UK’s media regulator, OfCom, for broadcasting hate speeches and incitement. An investigation has been launched into the charity he founded that funded them.
He was barred from the UK in 2010 but continued to operate the channels until last year.
The commission on Tuesday cited Mr Naik's channel as an example of Islamist extremism, which has led to a review of the powers available to the authorities to take action against acts of hate.
The commission's legal review, which will be led by the British former head of counter-terrorism Sir Mark Rowley, will examine incidents of abuse it has found that are not covered under current UK terrorism legislation or hate laws.
Extremism issues concern Islamist and far-right incidents.
The number of far-right prisoners convicted for terror offences in Britain climbed by one third last year to their highest recorded level.
They now account for more than one in six of all terrorists held in prison, according to official figures.
Islamist extremists still form the largest category of terrorism prisoners.