Police had to be called out after a 40-year-old man climbed onto scaffolding in Lancaster city centre last night and threatened to jump.
The man also threw pieces of wood and slates onto the street below during his four hour stand-off with police.
Meeting House Lane was closed between King Street and Fenton Street at around 9.30pm after police were called to a building covered in scaffolding close to the post office.
The man remained on the roof until around 1am, despite a negotiator being called in by police in an attempt to coax him down.
The man, of no fixed abode, eventually came down of his own free will and was arrested by police on suspicion of criminal damage.
He was still in custody on Wednesday morning.