Police have released new pictures of a girl who's been missing from her home in Milton Keynes for a week.
It's thought 16 year old Cailey-Anne Payne was last seen in the Acton area of London on Saturday morning.
Officers say they're treating her disappearance very seriously.
"As with any vulnerable young person, if you're 16 and you're away from home, that naturally causes concern for the police," Det Supt Barry Halliday told ITV News Anglia.
"If Cailey-Anne is watching this, she's not in trouble, but we do need her to pick up the phone, and not necessarily talk to the police, but talk to a friend, a family member. Just let us know that she's safe and well."
More top news
The Met Office has issued a yellow cold weather alert and there's the risk of snow in places later on Boxing Day.
Mostly dry and bright, but chilly. Frost tonight.
Most places will see bright or sunny spells through the day, but with a few showers around, especially during the morning.