A penny whistle was a type of flute that the Eighth Doctor pretended his sonic screwdriver was when he materialised in World War I. (AUDIO: The Great War [+]Loading...["The Great War (audio story)"], Fugitives [+]Loading...["Fugitives (audio story)"])
The Second Doctor once referred to his recorder as a penny whistle. (COMIC: Day of the Tune [+]Loading...["Day of the Tune (comic story)"])