A dramatic rise in arrests of women and teenagers has helped drive the number of terror suspects detained in Britain to record levels.
There were a total of 315 terrorism-related arrests in the year ending September 2015 - meaning the rate has jumped by more than a third (34%) in just a year as security services and police mount a huge effort to counter the threat following the rise of Islamic State.
It is the highest tally for a year to September on record.
Home Office figures showed the rise was in part down to increases in the numbers of female and under-18 suspects.
The number of women and girls held has more than doubled compared to the previous year to 50, meaning they now account for around one in six (16%) of all arrests after a rise of seven percentage points compared to the previous 12 months.
It also means that a fifth of all the arrests of females since 2001 have occurred in the last year.
The Home Office report said: "The majority of the increase in the number of women getting arrested has been linked to international-related terrorism."
Statisticians also reported a "notable increase" in the number of suspects aged under 18 being arrested, with the total of 15 detained over the year, the highest on record.
The statistics bear out warnings about increasing numbers of women and teenagers being drawn into extremism.
Schoolgirls and young families are among those feared to have fled the UK to join IS, also known as Isil or Daesh.
The figures also showed that:
:: There were increases in the number of terror-related arrests across all age groups compared with a year ago, but jumps in the 21-24 and 30 and over age groups together accounted for 86% of the overall rise.
:: Four out of five (79%) of those arrested were British or had British dual nationality. This proportion has increased considerably in recent years, the report said.
:: Terrorism-related arrests increased across nearly all ethnic groups, with jumps of 41% and 25% in the number of those who considered themselves to be Asian and white respectively.
:: The surge in police activity has also coincided with a rise in in the number of terrorists, domestic extremists and separatists being released into the community.A total of 120 were freed from custody in the year to June - double the number in the previous year. Of those 99 had served sentences, with many subject to licence conditions following their release.
Last month the spending review included a 30% increase in the dedicated counter-terrorism budget as the Government attempted to step up the UK's capacity following the Paris attacks.
Security Minister John Hayes said: "We are determined to detect, disrupt and where possible prosecute all terrorist threats to the UK.
"The figures released today once again highlight the hard work carried out by the police, Security Service and Crown Prosecution Service to keep the public safe – and emphasise the scale of that challenge.
"At a time of very significant threat, it is vital they have the powers they need to protect the British public."
Just over a third (35%) of those arrested were subsequently charged with terrorism-related offences, while 37% were released without any action. Others were charged with offences not related to terrorism, bailed or faced "alternative action".
Since officials first started gathering data in 2001, 66% of charges have been terrorism-related, with the report saying: "Police are charging suspects with a terrorism-related charge in an increasing proportion of cases."
It followed criticism from former government terrorism adviser Jahan Mahmood who told Sky News there are "simply too many arrests".
The Home Office said charges are likely to increase as there are a number of ongoing investigations.