In 1975, French producer Rodolphe Roffi arranged a champagne commercial starring Patrick Macnee and Linda Thorson. He thought that Agente speciale (1961) was still in production; learning that he was wrong, he was determined to revive the show.
Patrick Macnee had difficulty getting back into character as Steed. After being confronted with this by producer Albert Fennell, he found inspiration by watching The Benny Hill Show (1969) parody.
Purdey's character was originally called "Charly", but this was changed when it was realized that there was a perfume with the same name. Joanna Lumley suggested the name Purdey, after the most expensive and revered shotgun in the world (and also her onetime fellow model Sue Purdie).
Patrick Macnee refused to wear suits with seventies flares. He told the tailors at Gieves & Hawkes that Steed sets fashions, rather than follows them.
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."