Amy Winehouse went in voluntarily to the police station for questioning about headbutting a man early Wednesday morning and she was arrested.
A Scotland Yard spokesman said,

"I can confirm that a 24-year-old woman has been arrested by appointment at a central London police station and is currently in custody."

This all came after a 38 year old man filed a report against Amy claiming that she headbutted him. That same night she also supposedly punched another guy in the face.
WOAH, that's either the drugs talking or else Amy has some SERIOUS anger management problems.