The number of terrorism suspects being arrested in the UK has reached record levels as police combat the threat posed by Islamic State.
In the year to March, 299 people were detained for terrorism-related offences, an increase of 31% compared to the previous year, Home Office figures revealed.
It is the highest number since officials began collecting data in September 2001 and higher than the previous peak of 284, which was recorded in 2005, the year of the July 7 bombings.
Officials say there has been a "marked increase" in the number of those arrested who consider themselves to be of British or British dual nationality.
In 2014/15, they accounted for more than three-quarters of those detained for terrorism-related offences, compared with 52% in the year to March 2011.
The figures also showed that the number of 18 to 20-year-olds arrested more than doubled on the previous year from 20 to 43.
A large amount of the overall increase was driven by a spike in the last three months of last year, when there were 106 arrests.
The rate fell from January to March this year, with 67 terror-related arrests, but this was still higher than the same period in the previous two years.
A Home Office statistical bulletin setting out the data said: "Since 11 September 2001 the numbers of terrorism-related arrests have fluctuated.
"There was an initial spike in the number of arrests in the period soon after the September 11 attacks on the US and around the time that the US-led invasion of Afghanistan was beginning.
"There was a large increase in the number of arrests in the period immediately after the 7 July London bombings, where the number of arrests was at its highest since the data collection was established. Soon after this, the number of terrorism-related arrests declined, until late 2010.
"In late 2010, the Arab Springs began, and throughout the years since the initial uprising, the number of terrorism-related arrests in Great Britain has seen a steady rise."
'Step change in the terrorism landscape'
The total number of terror arrests in the UK since the Twin Towers atrocity 14 years ago is just short of 3,000.
The data also showed that a record 35 females were arrested on suspicion of terror offences after the number more than trebled in five years. The increase in women being arrested was driven by a surge between October and March.
Eight of those arrested were under 18.
Senior officers have recently warned of a step change in the terrorism landscape, with women and children increasingly at risk of radicalisation.
A string of high-profile cases have emerged in which women are said to have taken their children to territory controlled by IS in Syria.
There has also been a significant increase in the number of suspects arrested who were aged 30 and over, with a rise of more than a third compared to the previous year.
Of the 299 people arrested in 2014/15, less than half - or 100 - were ultimately charged with terror-related offences.
The Home Office said this was the highest proportion since records started, "suggesting that police were more frequently able to find evidence to support the link to terrorism following a terrorism-related arrest".
It is likely that the volume of terrorism arrests has risen further since the period covered by the statistics.
Last month Mark Rowley, the country's leading counter-terrorism officer, disclosed that suspects are now being held at a rate of more than one a day.
Fifty-six of the arrests related to international-related terrorism - defined as "activities linked to or motivated by any terrorist group based outside the UK". This was more than a third (35%) higher than 2013/14.
The number of suspects arrested over domestic terrorism - where there is no link to Northern Ireland or international groups, more than doubled from 15 to 32.
Security Minister John Hayes said the Government is determined to detect and disrupt all terror threats to the UK.
He added: "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."
Laws rolled out earlier this year have "bolstered our already considerable armoury of powers to disrupt the ability of people to travel abroad to fight, reduce the risks they pose on their return and combat the underlying ideology that feeds, supports and sanctions terrorism," he said.
Mr Hayes said the forthcoming Investigatory Powers Bill, covering the controversial issue of security services' access to communications data, will ensure they are "equipped with up to date capabilities to protect us from those who would seek to do us harm."