It serves as a "final wink" to the audience, undercutting the heavy sentimentality of the preceding track, "Nan's Song" (a tribute to his grandmother), with absurd humor.
The song mocks the "rock star" lifestyle, specifically referencing excessive wealth (the yacht) and the public's perception of his eccentricities.
"Shall I fanny about on a yacht? / Stop start now it's started stop"