is a very notable example of remaking episodes, as several of the later colour Rigg episodes were straight down the line reuses of Honnor Blackman scripts.
Officially, the excuse was the show was now selling in America and Americans hadn't seen the videotaped episodes so why not reuse them (that seems a bit heartless on the British viewers only a couple of years removed from the original broadcast, but by the time it went into "Color" The Avengers
was basically an American series, the B&W Emma Peel season was the last to actually be commissioned by ITV, after that all renewals were down to the Yanks).
However, there is something a bit odd about all this suggesting something a bit more than just wanting to get good scripts out there in America. All the remakes happen fairly closely together in the colour Rigg episodes, both before and after there aren't any, despite there being a few more they could have done in the film era style.
Being a series that involves Brian Clements and Terry Nation (two men who never let a good idea go to waste), there are lots of examples of episodes reusing ideas from previous ones (The House That Jack Built
has a lot in common with Don't Look Behind You
, which ironically was one of the episodes they remade later, as The Joker
), but word for word remakes are just contained within that very brief period of the show's run. It creates the impression there were some serious behind the scenes problems that meant they needed some easy to use scripts in a hurry.
Vaguely on thread: The character who gave The Avengers
its name in the first episode was played by Patrick Macnee's one time wife and future squeese of Dr. McCoy Catherine Woodville.