The vast majority of the 1960s episodes no longer exist in the BBC archives, and it appears that several 1970s episodes are lost as well; allegedly because of rights issues plus costs, these were wiped.
When Massive Attack (and Shara Nelson) appeared to perform their single "Unfinished Sympathy" in February 1991, they were credited as Massive following pressure from the BBC to drop the "Attack" from their name due to the Gulf War that was ongoing at the time.
Kylie Minogue is the female singer to have appeared the most times on the show, with 50 appearances from 1988- 2004. She was unable to appear on the show in 2005 to perform her single "Giving You Up" due to being diagnosed with breast cancer, from which she would later make a full recovery.
In November 1999, former Spice Girls member Geri Horner and contemporary Spice Girl Emma Bunton released singles on the same day, leading to a well-hyped "chart battle" between the pair. The battle ended on this show, when Geri was revealed to have won after getting to #1, with Emma's single "What I Am" at #2. Both performed on the episode. Hhaving pre-recorded her performance Geri lip-synched the song, while Emma appeared in the studio and sang live.
A memorable (for the wrong reasons) moment came when the British group All About Eve made their first appearance on the show in August 1988, to perform their new single "Martha's Harbour". As the song began playing, a technical error resulted in everybody apart from the group being able to hear it, but lead singer Julianne Regan simply sat on stage, unaware she was supposed to be singing. By the time she was informed the song was playing, it was almost over, resulting in her only actually performing the last verse. The group was invited back on the following week, with Regan choosing to sing live.
When BBC director Bruce Gowers' short film of Queen performing "Bohemian Rhapsody" aired during a 1975 episode, it created a milestone due to its role in prompting record companies to produce promotional videos for artists' single releases as a common practice.
Since 2012 the BBC has avoided showing any episodes from the program featuring Jimmy Savile in case it causes offense to the victims of Savile's lifetime of sexual abuse. Following Dave Lee Travis' conviction in 2014 for indecent assault, the BBC also announced it would not be repeating episodes presented by Travis either.
By 2015 BBC Four was repeating many surviving episodes seemingly complete and uncut from the original first transmission, re-issued under the BBC Music branding. It can be safely assumed that any surviving episodes withdrawn from repeats have been withdrawn due to music rights clearance issues--costs, music publishers, performance and/or performer clearances, and/or disgraced "Top of the Pops" presenters and/or disgraced music acts / performers.
By 2015, due to the BBC's withdrawal of editions featuring appearances of certain disgraced "Top of the Pops" presenters and / or music performers throughout the entire series, making a quantity of unedited repeats impossible, it can be safely assumed that some of the later performance archive compilations "salvage" re-usable performances. This is most obvious with the Christmas compilation editions, where certain Christmas performances have been taken from editions that aren't seen in repeats of the unedited versions, but would have been in the same original editions as certain disgraced presenters and/or performers.