"The Skye Boat Song"
From Tardis Wiki, the free Doctor Who reference
"The Skye Boat Song" was a tune that the Second Doctor played on his recorder near the conclusion of the London Event. It was in part a diversion to prevent Colonel Lethbridge-Stewart from overhearing his discussion with Jamie McCrimmon on the Picadilly Circus tube station platform. (TV: The Web of Fear)
Behind the scenes
The song as played on bagpipes.
The work is not identified through dialogue, but simply through a very clear rendition played by Patrick Troughton.
