A woman has been arrested at Luton Airport on suspicion of terror offences.
The woman, a British 21-year-old, had landed at the airport after a flight from Istabul, Turkey.
She was arrested on suspicion of preparation of acts of terrorism, under Section 5 of the Terrorism Act 2006.
She is currently in custody at a south London police station.
Inquiries are continuing, Scotland Yard has said.