The figures released by the UK Home Office today also marked a dramatic rise in the number of under-18s detained that increased from eight to 15 - the highest-ever level.
A record 315 terror suspects were arrested in the past year, with the number of women arrested for terrorism-related offences more than doubled in the 12 months to September from 21 to 50, the figures showed.
The 31 per cent rise in the number of suspects arrested for international-related terrorism reflects a concentrated effort by the police and security services to counter the threat from the Islamic State (ISIS).
"Furthermore, individual investigations involving multiple suspects are likely to cause an increase in the figures more than investigations involving small numbers of suspects," it added.
Schoolgirls and young families are among those feared to have fled the UK to join ISIS, also known as ISIL or Daesh.
Females now account for around one in six - or 16 per cent - of the total counter-terrorism arrests throughout the year.
The proportion of terror suspects who are British has risen sharply to 79 per cent of those arrested this year, compared with 56 per cent in 2001 when the statistics were first collected.
The 37 per cent arrested then released without charge is a slight increase over the previous year's 31 per cent but far below the 53 per cent who were detained and released in 2013.
