Arrests for terrorism-related offences have fallen from peak levels as a dramatic recent surge shows signs of slowing.
The number of suspects held as part of counter-terror investigations had soared to record levels of around one a day amid unprecedented efforts to contain the threat.
Official figures released on Thursday show that in the year ending September 30, there were 255 arrests for terrorism-related offences.
This was a fall of a fifth compared to the previous year, when there were 317.
A Home Office report on the data said: "Although the number of arrests has fallen, it is still relatively high when compared to other recent years."
The official threat level for international terrorism in the UK is currently severe - meaning an attack is "highly likely".
It has stood at the level for more than two years in the wake of the rise of Islamic State.
It was revealed in October that Britain's security services and counter-terrorism units have foiled at least 10 attacks in the past two years.
Around 850 people linked to the UK and regarded as a security threat are believed to have taken part in the Syrian conflict, with just under half thought to have returned to the country.
There was a fall in the proportion of those arrested who were female, from 16% in the year ending September 2015 to 11% in the latest 12 months, the new figures showed.
There were reductions in the number of arrests across all age groups compared with the previous year- except for under-18s, which remained the same, at 15.
The number of individuals arrested for international terrorism fell by 13%, from 241 arrests to 210, and arrests for domestic terrorism fell from 27 to 19.
Arrests dipped across all ethnic groups except "other", with the biggest fall seen for those of Asian ethnic appearance.
Of the 255 arrests for terrorism-related offences, 96 had resulted in a charge - 78 terrorism-related and 18 non-terrorism-related - as of October.
The figures also showed a 25% drop in the number of examinations carried out under powers to stop and question individuals entering or leaving the country.
This has continued the gradual decline in the use of the power in recent years, the report said.