A 25-year-old woman was arrested today on suspicion of preparation of terrorist acts in connection with Syria.
Counter-terrorism officers took the young woman from Bedfordshire to a central London police station, where she remains in custody, Scotland Yard said.
Two addresses in Bedfordshire were being searched as part of the investigation. Police said the investigation is related to Syria.
The woman's arrest is the latest in a string of police raids on people living in Britain suspected of terror offences linked to the bloody conflict in Syria.
Last week, five men appeared in court accused of conspiring to shoot dead police and soldiers in London in a terror plot inspired by Islamic State - the jihadist militant group which has beheaded a number of Britons and other westerners in Syria.
The terror group, which is also known as Isis and Isil, wants to create an Islamic state across Syria and Iraq. It has been accused by human rights group Amnesty International of turning Iraq into "blood-soaked killing fields".
It is estimated that around 500 Britons have travelled to Syria to fight. Around 50 of those are thought to be British women.