W.S. Lloyd Webber (Andrew Lloyd-Webber's father) was an accomplished organist and church musician, and he wrote some really nice organ music, among which are the 6 Interludes on Christmas Carols. Here we hear the first of the set, "The Holly and the Ivy" (and it's interesting, the piece just sort of "suggests" the tune, but it's there....)
The pieces are wonderful (and a bit trickier than they look) and include some unusual purple twists of harmony.