More than two-in-five suspects arrested in terror investigations last year were white, official figures show.
In 2018, a total of 273 individuals were arrested on suspicion of terrorism-related activity in Britain.
Of those, 43% were of white ethnic appearance – a rise of nine percentage points on 2017.
The overall number of white suspects held, 118, was down by more than a quarter (26%) year-on-year, but it was the third highest for a calendar year since data collection started in 2001.
There were falls in arrests across all ethnic groups, according to the Home Office statistical report.
It said the largest fall was seen for those of Asian ethnicity, which decreased by 56% from 196 to 86 arrests.
“The proportion of white people arrested now exceeds the proportion of Asian people arrested,” the report said.
The total number of terror-related arrests in 2018 was down by 41% on the previous year.
But officials say the fall is partly explained by a large number of arrests made following attacks in London and Manchester in 2017.
The report said: “Whilst the 273 arrests made in the latest year saw the lowest number of arrests since the year ending December 2013, in each of the past five years the number of arrests has been above the annual average of 258 arrests over the whole time series.”
The statistics showed 171 arrests were registered in the “international” category. This covers suspected activity linked to or motivated by terrorist groups based outside the UK, such as Islamic State.
Sixty-six were logged in the domestic bracket, which includes cases where there is no connection to either Northern Ireland-related or international terrorism. Further breakdowns are not given but this section would include arrests relating to suspected far-right activity.
Of the 273 arrests: 102 (37%) resulted in a charge, of which 81 were charged with terrorism-related offences; 99 people (36%) were released without charge; 23 (8%) people were released on bail pending further investigation; 17 (6%) faced alternative action; and 32 (12%) cases were pending at the time data was provided.
Of the 81 people charged with a terrorism-related offence, 38 had been prosecuted, all of whom had been convicted.
As of the end of December, there were 221 people in custody in Britain who had been convicted of or charged with terrorism-related offences.
More than three quarters of the prisoners (79%) were assessed as having Islamist-extremist views, while 13% were categorised as holding far right-wing ideologies.
The number of Islamist-extremist prisoners held in custody saw a decrease of 9%, to 175, the report said.
It added that the proportion of prisoners holding far-right ideologies has increased steadily over the past three years, with the number up from 21 to 28 in the latest year.
Police and MI5 are running a record 700-plus live terrorism investigations as they confront a threat that security chiefs say is unprecedented in scale.
There are around 3,000 active “subjects of interest”, plus a wider pool of more than 20,000 “closed” SOIs who have at some point featured in probes.
Britain was hit by five attacks in 2017, while 14 Islamist and four extreme right-wing plots have been foiled in the last two years.
Deputy Assistant Commissioner Dean Haydon, counter-terror policing senior national co-ordinator, said: “We are still seeing an unprecedented level of activity across counter-terrorism policing, and the demands upon our national network have increased by about a third since the start of 2017.
“The step-change in terrorist activity is matched only by an increased effort from police and security services, who are working tirelessly to bring people to justice - which is evidenced by the impressive conviction rate achieved in the last year.”
He also highlighted the public’s role in helping tackle terror: “Many of these arrests, convictions and investigations hinge upon vital information provided by members of the public.
“So please, if you see anything suspicious or someone acting in a way that doesn’t feel right, tell police and you may well be playing a vital role in keeping the public safe or help us successfully convict those intent on doing us harm.”