Right-wing extremism is the fastest growing terrorist threat in the UK – with supporters seeking to mimic jihadist attacks, police have said.

The UK head of counter-terrorism Neil Basu said seven of the 22 plots foiled since March 2017 have been linked to far-right ideologies.

About 10% of around 800 live terror investigations were linked to right-wing terrorism, while the Government’s controversial Prevent programme has seen referrals nearly doubling since 2015/16 to 18%.

“It’s rising from a low base, but it’s probably the fastest growing bit of my casebook at the moment,” the Metropolitan Police Assistant Commissioner said at a briefing on Thursday

“I see it as my job, and the security service as my major partner, to stop that.”

Mr Basu said counter-terror police and MI5 have disrupted right-wing plots “designed to kill people”.

Attack methods used and planned have mimicked those seen in jihadist plots, including knife attacks and seeking to create improvised explosive devices, he told reporters.

Mr Basu said some of the Islamic State guidance materials were also being used by right-wing terrorists, although they tend to target specific demographics or individuals rather than launching indiscriminate attacks in a public place.

And he said the biggest threat still comes from Islamist and jihadist terrorists.

“Despite the increases, right-wing terrorism remains a relatively small percentage of our overall demand, but when nearly a third of the plots foiled by police and security services since 2017 relate to right-wing ideology, it lays bare why we are taking this so seriously,” he said.

“As a proportion of our overall threat it’s definitely increasing, whereas the Islamist threat is staying the same, albeit at a very high level.”

Mr Basu said the National Action group has been “decimated” since it was banned in December 2016 after members publicly praised Thomas Mair for the terrorist murder of Labour MP Jo Cox.

Right-wing extremists now operate within small groups across international borders online, with lone actors, who can be radicalised within weeks or days, posing the greatest threat, he added.

The counter-terror chief said young people and those with mental health issues are particularly vulnerable to becoming radicalised, with children as young as 14 linked to right-wing terrorism.

University students and members of the military have also been targeted.

“We are bringing the full might of the UK counter-terrorism machine to bear against those extremists of any ideology who wish to do us harm or incite violence,” Mr Basu said.

“And that is evident not only in the number of plots we have foiled, but also the number of convictions we have achieved and continue to chase through the courts.”

Last week, white supremacist Vincent Fuller, 50, was jailed for 18 years and nine months for stabbing 19-year-old Dimitar Mihaylov in what a judge called a “terrorist act”.

Three other right-wing terrorists, including a “16-year-old Nazi”, from Bradford, who was convicted of making a bomb in a bid to “kill many people” are due to be sentenced in Leeds and London on Friday.

But Mr Basu said police “can’t arrest ourselves out of this problem” and called on the public to come forward if they fear a friend or family member is becoming radicalised.

“I have been called ridiculously idealistic, but I believe more than ever that evil triumphs when good people do nothing,” he said.

“In the UK the Prevent programme is full of people who get up every day to do something to protect those who need our help, and I believe that is worth defending and fighting for.”

Mr Basu said both hate crime and right-wing terrorism had increased since the EU referendum, but pointed out that spikes were also seen after incidents such as Islamist attacks.

“This is not just about Brexit or the referendum. It’s an international problem,” he added.