The scale and impact of extremism across England and Wales will be laid bare in a landmark review set to be launched by a newly-created expert body.

In the coming months, the Commission for Countering Extremism (CCE) will carry out an intensive exercise of evidence-gathering with a view to publishing the first study of its kind.

Sara Khan, who was appointed as lead commissioner by the Government earlier this year, said it was an "important moment" for the CCE.

"I've already met with more than 300 experts and activists," she said.

"Communities are deeply concerned about the impact of extremism.

"Extremism is sowing division and hate, spreading fear and undermining democratic values and human rights.

"But it's also complex and changing - in 2018 the old stereotypes of far-right thugs and Islamist hate preachers don't always apply.

"Whether it's far-right, Islamist or other forms of extremism, we need to investigate their changing tactics such as a new-found professionalism, the intellectualising of hate and abusing the power of social media."

She said there is a need to understand modern-day extremism better so more people can challenge it.

"The public debate on extremism is increasingly polarised, leaving some nervous about speaking out," Ms Khan added.

"We need to investigate how we improve the debate around extremism, so it's more constructive.

"We must be prepared to follow the evidence and to be as radical as necessary when it comes to countering extremism."

Plans to set up the commission were announced by Prime Minister Theresa May in the wake of the Manchester Arena bombing in May last year - one of five terror attacks in Britain in 2017.

The body has been tasked with identifying and challenging all forms of extremism, advising ministers on new policies and promoting "pluralistic British values".

Neither the issue of terrorism, nor the Government's counter-terrorism strategy, including the Prevent scheme, are in the CCE's remit.

The new study into extremism will investigate the scale of the problem, the changing tactics of extremists and the current response.

It will review academic literature, commission bespoke research and take evidence from the public.

The Government has already committed to sharing information with the Commission, which will ask regulators, local councils, police forces, universities and other public and private bodies to follow suit.

Ms Khan also announced that she has created a new expert group to advise and challenge the CCE on its work.

Members of the panel include Sir David Anderson QC, the former independent reviewer of terrorism legislation, recently retired police counter-terror chief Sir Mark Rowley, and Dame Louise Casey, who led a major review into integration.

By Hayden Smith