Top of the Pops was the longest running weekly, music chart show featuring videos and performances on BBC1, UK which ran for over 42 years from 1 January 1964 to 30 July 2006 and featured around 2,000 episodes in total. The show saw many changes through the decades, in style, design, fashion and taste. Due to the BBC's former policy of deleting old programmes, the vast majority of the episodes from the first ten years of the programme's history have been lost. Of the first 500 episodes (1964–73) only about 20 complete recordings remain in the BBC archives. That's why only four of the seven ABBA studio performances exist in their full-length episodes). The 1976 Mamma Mia performance exists only in a Christmas retrospective episode; So Long from 1974 has been found thanks to the help of ABBA fans c/o this ABBA on TV website but it is feared the performance of SOS from 1975 is wiped forever.

Episode 613

ABBA's UK visit was from 30 September - 2 October 1975.

They performed SOS LIVE on Top Of The Pops, originally introduced by Jimmy Savile with Noel Edmonds introducing the repeated clip on 16 October 1975 and Ed Stewart introducing the same clip on 30 October 1975. All three episodes are missing from the BBC TV archives but at least if there are home video copies of it there's three chances to find it! (However, this would depend on whether it was ever "sold" abroad. It seems unlikely with the song publishing rights and different labels around the world for various groups - plus the British BBC charts (on which Top Of The Pops was based) wouldn't mean much elsewhere. But I suppose there are three programmes including this clip so there's three times the chance than if it was just shown the once. I am ever hopeful).

The pictures above are confirmed as being Top of the Pops because one of the pictures was submitted by a book publisher for inclusion in Carl Magnus Palm's book, ABBA - The Complete Guide To Their Music. To back this up, the picture is also used on the Top of the Pops web-site. The third picture above, featured in ABBA - The Scrapbook by Jean-Marie Potiez, also confirms it as Top of the Pops.

In the darkest reaches of my mind the bubbles at the back in the pictures below do seem strangely familiar to me. I was only 10 years old at the time but my interest in ABBA had already been sparked.

Until the fourth picture above turned up in ABBA - The Scrapbook, the combination of Frida in long cat dress and Agnetha wearing jeans under her short cat dress seemed an odd one. Now it is clear they were merely rehearsal pictures. The fourth picture above must be from the actual performance.

Other guests on this edition:

1. Mud - La La La Lucy
2. Jonathan King - Una Paloma Blanca
3. The Four Seasons - Who Loves You (danced to by Pans People)
4. Mac & Katie Kissoon - Like A Butterfly
5. ABBA - SOS
6. Carl Malcolm - Hey Fatty Bum Bum
7. Art Garfunkel - I Only Have Eyes For You
8. The Chi-Lites - It's Time For Love
9. The Goodies - Nappy Love
10. David Essex - Hold Me Close

This performance was repeated on 16 and 30 October 1975 on Top of the Pops as the song rose in the charts, but all three clips are missing from the archives.

The audio clip is from the 16 October 1975 broadcast (because it's introduced by Noel Edmonds).  That week SOS had entered the Top 10 of the UK at number 7 and in the following two weeks it reached number 6 - its highest position.  

Top of The Pops (Waterloo), 1974; 
Top of The Pops (Waterloo), 1974; 
Top of The Pops (So Long), 1974; 
Top of The Pops (Waterloo), 1974; 
Top of The Pops (SOS), 1975;
Top of The Pops (Mamma Mia), 1976; 
Top of The Pops (Fernando), 1976;
Top of The Pops (Christmas greeting), 1978;
Top of The Pops (Frida), 1982; 
Top of The Pops (Agnetha), 1983; 

Thanks to Carl Magnus Palm for identifying this entry. Extra thanks to Alex Jones, Jozsef, David Calverley and Roy Taylor.  Also thanks to "EricandDish" on YouTube for pointing out the third picture shown featured in ©ABBA - The Scrapbook by Jean-Marie Potiez.  Thanks to Eduardo Oscar Diconza c/o YouTube.
Thanks to the website Popscene