- "The Blorgons' Cunning Scheme": Layla's Heroic Sacrifice halfway through the serial set the precedent for how Anyone Can Die, even Associates, in the programme.
- "The Lost Asteroid": The first metamorphosis episode—swapping the First Inspector with the Second—must have been a huge whammer for the contemporary viewing audience way back in the 1960s.
- "The Crime Sports": It wasn't enough that Susannah Overseer returned for a hasty but significant cameo, never to be seen again. Even more surprising, the mysterious background figures glimpsed throughout Season 6 were finally revealed to be the then-unnamed Infinity Knights' Internal Affairs Watchdogs—and they were not happy with the Inspector's conduct on his enigmatic mission.
- "The Three Inspectors": In the final installment of the serial, the future Inspector reveals that Yosif is a girl.
- "The Theft of Space": King Sonacry dies. It is revealed that Barbartron is populated with the descendents of exiled Kayaclaschians. And then, Reena, having finally come into her own as a Lady of War, has just finished her coronation speech and watched the Inspector proudly depart when she is literally stabbed in the back by the traitorous Constable Dredan.note
- "Mathsville": It was a real surprise for the Inspector to metamorphose into a woman as BTV had kept Lynda Bellingham's casting under wraps by floating the rumour she would be a new associate.
- "Corporation of the Blorgons": The Orange Warden returns and gives the Blorgons their "powerboating licence", removing one of the race's major weaknesses. The Blorgon Commonwealth of Sentients collapses into three hostile factions. And then Jeffrey dies.
- "Odyssey's Beginning": Yorke casually mentions that he is also one of the Time Deviants that the Inspector has been pursuing.
- "Brooke Gets Hitched": The mysterious voice telling the Inspector "It's time for quiet, time to rise" wouldn't be explained until "Nothing But Blorgons" in Series 7 since the next episode was the universally reviled "1981 Inspector Spacetime Holiday Special".
- "The Alias of the Inspector": When you think the episode is finished, there is a man standing in the dimensioniser revealing himself to be the Unknown Inspector!
Wham Episode / Inspector Spacetime
In the fifty years that Inspector Spacetime has been on the air, the programme has inevitably chalked up numerous wham episodes.