Patrick Macnee played secret agent John Steed throughout the series, complete with bowler hat and umbrella (both of which turn out to be full of tricks). In the first series Steed was himself a secondary character, the protagonist being Dr. David Keel (Ian Hendry) - all but two of these episodes are now lost. The Avengers was a successor (but not, as sometimes stated, a direct sequel) to Hendry's earlier series Police Surgeon, in which he played a similar character.
In subsequent series, Steed is accompanied by a female partner, in chronological order: Cathy Gale (Honor Blackman), Mrs. Emma Peel (Diana Rigg), and Tara King (Linda Thorson).
The classic Avengers episodes are generally considered to be those featuring Macnee and Rigg. This era was characterised by a futuristic, science fiction bend to many of the tales, with mad scientists and their creations causing havoc in their wake. However, earlier eras of the show had a much more hard-edged tone, with the Blackman episodes including some surprisingly serious espionage dramas (when viewed through the prism of the later, better-known period). Steed and his associate were charged with solving the problem in the space of an hour-long episode and thus preserved the safety of 1960s Britain on a regular basis. There was also a notable fetishistic undercurrent in many episodes (most notably the B&W Rigg episode "A Touch of Brimstone", in which Mrs. Peel, dressed as a dominatrix, becomes the "Queen of Sin"), and Macnee and Blackman released a novelty song called "Kinky Boots". (Some of the clothes seen in The Avengers were designed by the clothing designer John Sutcliffe, who also published the AtomAge fetish magazine).
The arrival of Rigg coincided with the show's sale to US television. Previously the series had been shot on 405-line videotape, with very little provision for editing and virtually no location footage. This meant that to all intents and purposes the Blackman episodes were shot live in the studio. Many of these episodes were wiped; those that survive are in the form of 16mm film kinescope recordings.
The US deal meant that the producers could afford to shoot the series on 35mm film. In any case, the change was essential because British videotapes were incompatible with US standards. The transfer to film meant that episodes could be shot like movies, giving the show much greater flexibility. After one filmed season in black and white, The Avengers began filming in colour in 1967, although it would be two years before British viewers could see it that way.
In the 1970s the series was revived as The New Avengers, with Macnee reprising his role as Steed, this time with two new partners, Mike Gambit (Gareth Hunt) and Purdey (Joanna Lumley). This time the series was produced independently by original series producers Brian Clemens and Albert Fennell, with French and later Canadian backing. Two seasons totalling 26 episodes were produced.
A recent newspaper report suggested that Macnee himself was responsible for tracking down the original negatives of both series for remastering, because he was tired of seeing inferior copies. If this is true, he is to be congratulated, especially since there seems to be no financial incentive.
A 1990s movie based on Macnee and Rigg's characters from the TV series, starring Uma Thurman and Ralph Fiennes respectively, received poor reviews. The original British poster showed Fiennes and Thurman accompanied by the caption: "He's Steed. She's Mrs. Peel." The frequent and inevitable response was, "No they're not! Patrick Macnee and Diana Rigg are Steed and Mrs. Peel!"
The Avengers series five title sequence was lovingly parodied in the title sequence for In Bed With Medinner.