Flag on a ship leaving port (4,5)

I believe the answer is:

blue peter

(Other definitions for blue peter that I've seen before include "Flag flown to warn of a ship's departure" , "Flag flown when about to leave port - TV programme" , "Ready-to-sail flag" , "Signal flag - children's TV programme" , "Waver before leaving" .)

I've seen this clue in The Guardian.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.