Roger Marshall(1934-2020)

He left Agente speciale (1961) because of differences with head writer Brian Clemens, whom he thought didn't allow him enough freedom.

[on working with Brian Clemens in Agente speciale (1961)] The name of the fecund and indefatigable Brian Clemens is all over the show. No exaggeration to say his influence pervades almost every scene. Lead writer, associate producer and story editor. In my book that was at least one job too many. I wrote six episodes for the first Diana Rigg series-Clemens and I wrote 50% of the series between us-only two of which... three at the most... I can view with pride and pleasure. Working on the show had started to become a chore. No longer was a writer able to write what he wanted and in the way he wanted. Wit and style were being squeezed out. It was time to say goodbye.