Which song was the UK number one Christmas single of 1979?

"Another Brick in the Wall" is a three-part composition on Pink Floyd's 1979 rock opera "The Wall", written by bassist Roger Waters. "Part 2", a protest song against rigid and abusive schooling, features a children's choir. At the suggestion of producer Bob Ezrin, Pink Floyd added elements of disco.

"Another Brick in the Wall (Part 2)" was released as a single on 23 November 1979, Pink Floyd's first in the UK since "Point Me at the Sky" (1968). It was also the final Christmas number one of the decade in the UK. In the US, it reached number 57 on the disco chart. The single sold over 4 million copies worldwide. Cash Box described it as a "catchy but foreboding selection, with its ominously steady drum work and angry lyrics."

Pink Floyd were an English rock band formed in London in 1964. Gaining an early following as one of the first British psychedelic groups, they were distinguished for their extended compositions, sonic experimentation, philosophical lyrics and elaborate live shows. They became a leading band of the progressive rock genre, cited by some as the greatest progressive rock band of all time.