A record 400 arrests were made for terror-related offences in Britain in the year to the end of September 2017.
The figures have been released by the Home Office a day after an alleged plot to kill the Prime Minister was revealed.
There have also been allegations that Prince George may have been the target of a separate plot.
The total included 64 arrests in connection with attacks in Westminster, Manchester, London Bridge, Finsbury Park and Parsons Green.
Of the arrests made over the year, 115 resulted in a charge, 213 were released without charge, 60 were released on bail pending further investigation, 11 faced “alternative action”; and one case was pending.
Out of those who were charged, 97 (84%) were charged with terrorism-related offences.
It was also revealed that 58 of those held were female – the highest number on record.
Security minister Ben Wallace said police and security services “have been clear that we are facing a shift rather than a short-term spike in the terrorist threat”.
He added: “The statistics we are publishing today demonstrate the breadth of work that they undertake, alongside the rest of the criminal justice system, day in and day out to keep us safe.
“But this is not the totality of our work. The whole of society must come together to challenge the terrorist threat.
“The public must remain alert but not alarmed and report any suspicions they have about unusual activity or behaviour to the appropriate authorities.
“Furthermore, the Government is reviewing its counter-terrorism strategy in light of recent attacks to ensure we meet the threat from terrorism now and in the future.”
On Tuesday, MI5 said it had prevented nine terror attacks in the past year, while the agency’s boss Andrew Parker warned the threat to the UK is evolving at a scale never seen before.
But after a series of devastating attacks in the UK, questions remain over whether security services are effectively fighting the threats, and whether they have enough resources.
Earlier this week, Home Secretary Amber Rudd told Parliament that the Manchester Arena bombing, which killed 22 people, could conceivably have been averted if intelligence had been used differently.
In October, Mr Parker told Sky News that the threat to Britain is “multi-dimensional”, adding: “It’s at the highest temp I’ve seen in my 34-year career.
“Today, there is more terrorist activity, coming at us more quickly, and it can be harder to detect.
“We’re now running well over 500 live operations involving around 3,000 individuals known to be currently involved in extremist activity in some way.
“As well as those we are looking at today, risk can also come from returnees from Syria and Iraq and also the growing pool of over 20,000 individuals we’ve looked at in the past in our terrorism investigations.”
Ms Rudd has said she is planning to toughen up penalties for those found viewing terrorist propaganda online.
(c) Sky News 2017: Terror-related arrests have reached record high, Home Office figures show