The number of white suspected terrorists being arrested in the UK has overtaken those of Asian appearance for the first time in more than a decade.

Statistics released by the Home Office show an overall fall in terror arrests of 22 per cent in the year, with 351 made in the 12 months to the end of June.

“The fall is partly due to a relatively large number of arrests being made following terrorist attacks in London and Manchester last year,” a report said.

White suspects accounted for 38 per cent of terror-related arrests, followed by those of Asian appearance on 37 per cent and black suspects on 9 per cent.

“This was the first time, since the year ending June 2005, that the proportion of white people arrested has exceeded the proportion of Asian people arrested,” the report said.

“It was the second highest number of arrests of white people in a year since the data collection began in 2001.”

The demographics of terrorists in prison, where Islamists make up the majority, is also changing, as the number of far-right extremists jailed rises.

The Home Office said: “The number of Islamist, extremist prisoners saw a slight decrease for the first time.

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“The proportion of prisoners holding far-right ideologies has increased steadily over the past three years, with the number up from 10 to 28 in the latest year.”

Terror arrests have risen significantly since Isis declared its so-called “state” across Syria and Iraq, causing at least 900 people to leave the UK for its territories and others, who remained in the country, arrested for raising money for the group, spreading its propaganda and planning to commit attacks.

Then in 2016, National Action became the first far-right group to ever be declared a terrorist organisation in the UK, with waves of police raids targeting the neo-Nazis.

Experts have warned of the threat of “reciprocal radicalisation”, where Islamists and the far-right feed off each other to drive support to their own ideologies.

Since the Westminster attack in March 2017, security services have foiled 13 Islamist plots and four from the extreme right-wing, seeing numerous would-be killers jailed.

Of the five attacks launched in London and Manchester last year, leaving a total of 36 victims dead, Isis claimed responsibility for four and one was carried out by a far-right extremist targeting Muslims.

Islamists make up 82 per cent of terrorist prisoners, followed by 13 per cent far-right and the rest made up of other ideologies including links to Northern Ireland.

Police leaders said the past year saw highest number of terrorists tried and successfully convicted, since data collection began in 2009.

Life sentences were handed out in 10 cases, including for the men who mounted the Finsbury Park and Parsons Green terror attacks.

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Deputy assistant commissioner Dean Haydon, a senior coordinator for national counterterror policing, said: “At a time when we are still seeing unprecedented levels of demand across CT Policing, we are still working tirelessly to ensure that our investigations yield positive results at court.

“It is a testament to the hard work and dedication of our officers and support staff, not just in London but across our 11 Counter Terrorism Units nationwide.

“We’re not only successfully prosecuting more people than ever before, but we’re also jailing the most dangerous offenders for longer – helping to keep the public safe.”

Police warned that the fall in terror arrests was linked to a decrease in the large-scale operations seen after last year’s attacks, and “should not be mistaken for a reduction in the threat or police activity”.

The number of active investigations being carried out by specialist police and the security services has reached it’s highest ever level, currently standing at more than 650 probes focusing on the “most dangerous individuals”.

“Demands upon CT Policing have increased by about a third since the start of 2017,” said deputy assistant commissioner Haydon.

“The step-change in terrorist activity is matched only by an increased effort from police and security services, and our officers are working incredibly hard to protect the public and to bring people to justice, which is evidenced by the impressive conviction rate achieved in the last year.

“But I would also like to use this opportunity to remind the public that they, too, play a part in these successes.

“Many of these arrests, convictions and investigations hinge upon vital information provided by members of the public.”

The figures came as the government consults on new terror laws contained in the Counter Terrorism and Border Security Bill.

If enacted, it could spark a dramatic increase in terror arrests, which are currently being made under two Terrorism Acts, by introducing new crimes.

They include viewing terrorist propaganda online just once, entering “designated areas” abroad, and making “reckless” statements that could drive support for a banned group.

People are urged to report suspicious activity online at www.gov.uk/ACT or via the confidential hotline on 0800 789 321.