@sarahdal I going to vote for the 1,000th episode, which was broadcast on 5th May 1983.
Unfortunately because it featured pretty much every then current and past presenter, it will never be shown again on the BBC, but just look at this track listing: https://totparchive.co.uk/episode.php?id=997
Britain's longest running pop music show celebrates its 1,000th edition. Since its first transmission on 1st January 1964, Top of the Pops has provided a weekly programme reflecting the bands and artists in the current hit parade. Included in this special edition are video clips and personalities from the past 19 years, plus a look at the top pop records from in the charts. Including performances from The Human League, Thompson Twins, Spandau Ballet, and Heaven 17.
--Top of The Pops 1983 05 05 [BBC] (Jimmy Savile+Peter Powell+Simon Bates) x264 (Kes-CVrt) 1000 Th Episodeto many DJS to mention
saraaaaargh
Flippin' 'eck, Tucker!