Home Office figures reveal a total of 100 people went to trial in the year ending 30 June 2018 – an increase of 39% on the previous year.
Of those, 90 were convicted, the highest number since data collection began in 2009.
The figures show a total of 351 arrests were made where terrorism-related activity was suspected.
Out of these, 133 were white and 129 were recorded as Asian ethnic appearance.
White people arrested on suspicion of terrorism accounted for 38% of terrorist-related arrests in the latest period – an increase of four percentage points on the previous year.
The proportion who were of Asian appearance fell by seven points to 37%.
The Home Office report said: “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 figures cover the use of anti-terrorism powers in Britain, and reveal that 234 arrests were registered in the “international” category.
This includes suspected activity linked to or motivated by terrorist groups abroad such as Islamic State.
Further breakdowns are not included in the statistics but this section would include arrests relating to suspected far-right activity.
Police and the security agencies say they are pursuing an unprecedented 650-plus “active” terrorism investigations.
Counter-terror police senior national co-ordinator, Deputy Assistant Commissioner Dean Haydon, said: “We may have seen a reduction in the number of arrests in the last 12 months, but we should put that in context by saying that we prevented 13 Islamist-related and four extreme right-wing plots since March 2017, so it certainly doesn’t indicate a reduction in the threat we all face from terrorism.
“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.”
Of the 351 arrests, 120 (34%) resulted in a charge, of which 92 (77%) were terrorism-related, 184 (52%) were released without charge, 29 (8%) were released on bail pending further investigation, and 18 (5%) faced “alternative action”.
Out of the 92 individuals charged with a terrorism-related offence, 48 were prosecuted, and 46 of those were convicted and two were found not guilty.
Forty-one people were awaiting prosecution, two were subject to “other outcomes” and one had no action taken against them.