The Persuaders! (ITV, 1971-1972), The Protectors (ITV, 1972-1974), and The Adventurer (ITV, 1972-1974) - resoundingly poking fun both at the genre they were imitating and the sources of their inspiration." Clemens cast Diana Rigg to replace departing star Honor Blackman in The Avengers. He was later quoted as saying, "I didn't do Diana a very good service. It made her an international star but I think I could have done more for her as far as the script was concerned. She was rather a stooge to Patrick Macnee's Steed." He did not choose Linda Thorson to replace Rigg. Producer Clemens created the BBC TV sitcom My Wife Next Door (1972) but left the scriptwriting to Richard Waring. The series won a BAFTA Award for Best Situation Comedy Series. Made around the same time, the TV movie The Woman Hunter was scripted by Clemens and fellow ITC writer Tony Williamson from the former's story. It was Clemens' first American credit. He followed this with a twist-in-the-tail anthology series Thriller (ITV 1973–1976; also known as Menace), for which he wrote all the stories as well as 38 of the scripts. In the mid-1970s, Clemens sued fellow writer Terry Nation for plagiarism, claiming he had given the concept of the 1975 TV series Survivors to Nation in the late 1960s and that had he registered the idea with the Writers' Guild of Great Britain in 1965. Nation strenuously denied the claim. Both sides agreed to discontinue the case due to escalating legal fees. Clemens' company The Avengers (Film and TV) Enterprises Ltd created a French/Canadian/British co-production, The New Avengers (ITV 1976-1977). The series cost £125,000 an episode to produce and was not a critical success, but sold to 120 countries. To cast the central female role of Purdey, Clemens considered "about 700 girls", interviewed 200, read scripts with 40 and screen-tested 15 before choosing Joanna Lumley. His company Avengers Mark One Productions went on to produce The Professionals (ITV, 1977–1983). In the early 1980s he was twice asked to produce a U.S. version of his most successful series - The Avengers U.S.A. for producer Quinn Martin and The Avengers International for Taft Entertainment but neither version materialised. An earlier attempt by Clemens at a US-based Avengers-style series resulted in his writing and co-producing the hour-long pilot film Escapade which was aired by CBS in 1978; again, this project did not proceed to series.