"Christmas Alphabet" is a Christmas song written by Buddy Kaye and Jules Loman, first released in 1954 by The McGuire Sisters
In 1955 it;s more well known counterpart recorded by Dickie Valentine became a number-one hit in the UK Singles Chart a version produced by Dick Rowe. It first entered the UK chart on 25 November 1955, where it spent seven weeks. Three of those were at No. 1. in 1955.
It is also the first Christmas chart topper that is actually about Christmas, a trend that would continue off and on over the next several decades.
References
Christmas Alphabet Wikipedia(Text) CC BY-SA