LONDON - The number of terrorists brought to justice following investigations in Britain has reached its highest level in nearly 10 years, according to figures from the British Home Office on Thursday.

A total of 100 people were brought to trial in the year ending on June 30, 2018, an increase of 39 percent from the previous year, while 90 were convicted -- the highest number since data collection began in 2009.

Terrorist-related arrests fell by 22 percent, from 449 to 351, though this is due to a spike in arrests after the five terror attacks occurred in Britain last year.

The deputy assistant commissioner, Dean Haydon, said that the number of active investigations had risen to more than 650, its highest level.

"Demands upon counter terror policing increased by about a third since the start of 2017," he added.

British police have warned that the terrorist threat facing Britain remains severe despite a fall in the number of suspects arrested.

Senior officers stressed the dip should not be read as indicating a reduction in the scale of the risk, saying the fall was mainly due to a spike in arrests following attacks in the previous reporting year.

"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," Haydon said.

"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," Haydon added.