The terror-related arrest of a teenager at Heathrow airport was not made in response to any immediate risk or threat, police said.
A 19-year old man has been arrested on suspicion of "preparing for acts of terrorism" in relation to Syria.
The man is currently held at a police station in London.
More top news
A five-year-old boy whose surprise meeting with "Spiderman" became an online hit has died.
It's going to feel very cold in parts today, with temperatures between 3C and 6C before falling to as low as -6C in some areas overnight.
A son paid off his parents' mortgage for Christmas - reducing them to tears.