Terror suspects are being arrested at a record rate as security services attempt to contain the unprecedented threat.
Official figures show there were 304 arrests for terrorism-related offences in Great Britain in the year to the end of March this year.
This was an increase of 18% on the previous 12 months, and the highest number in any financial year on record since data collection started in September 2001.
Of the 304 arrests, 108 resulted in a charge, including 91 suspects charged with terror-related offences.
One hundred people were released without charge, 88 were bailed pending further investigation and eight faced "alternative action".
The tally for 2016/17 includes 12 arrests made as part of the investigation into the Westminster attack in March. All were released without charge and told they would face no further action.
Since the Westminster atrocity there have been two more deadly attacks, in Manchester and London Bridge, while counter-terror agencies have foiled five alleged plots.
The scale of the threat facing the country has been laid bare with figures showing police and MI5 are involved in 500 investigations involving 3,000 individuals at any one time.
There are also 20,000 former "subjects of interest" whose risk must be kept under review.
The new figures, released by the Home Office, show that in 2016/17:
:: "International terrorism" accounted for three-quarters of the terror-related arrests, while 16% were logged in the domestic terrorism bracket;
:: The increase in the total number of arrests was driven by a sharp rise in the number of individuals from white ethnic groups held, up from 68 to 113;
:: The number of British nationals arrested has passed 2,000 for the first time since current records began, standing at 2,001;
:: Stops made at ports, airports and railway stations under counter-terror powers fell by 31% to 18,103, continuing a decline in the use of the measure in recent years.
The report also said that at the end of March there were 186 people in custody in Great Britain for terrorism-related offences or domestic extremism - an increase of 15% compared with the previous year.
International terrorism refers to activity linked to or motivated by any terrorist group that is based outside the UK which operates in and from third countries, other than Northern Ireland.
Domestic extremism covers activity where there are no links to either Northern Ireland-related or international terrorism.