Patrick Macnee had difficulty getting back into character as Steed. After being confronted with this by producer Albert Fennell, he found inspiration by watching Benny Hill spoofing The Avengers on his TV show.
Purdey's character was originally called "Charly", but this was changed when it was realized that there was a perfume with the same name. It is rumoured that Joanna Lumley suggested the name Purdey, after the most expensive and revered shotgun in the world.
The opening credits for the first 7 episodes of series one were edited out the first five episodes of the series, mainly "The Eagle's Nest" and "The Midas Touch". However, one shot featuring Joanna Lumley with long hair and Gareth Hunt in jeans was actually from their combined screen-test instead of an episode. From episode 8 onward, animated opening titles were used.
The last four episodes were made in Canada, under a production agreement that kept the second season afloat after the French co-producers failed to come up with all the promised finance. These episodes, dubbed "The New Avengers in Canada", are considered the worst of the series. Brian Clemens said "Canada is the worst place to film anything, it's such an empty sort of nothing. I'd rather have shot them in Los Angeles, which at least has an identity, but Canada always looked like Milton Keynes with snow."
Diana Rigg, co-star of the original Avengers, declined an invitation to appear on the new series. Instead, archive footage from the The Winged Avenger and From Venus With Love was used in one episode (K is For Kill Part One - The Tiger Awakes) to allow Emma Peel to make a guest appearance.