In January 2005, Tony Robinson told ITV's This Morning that Rowan Atkinson is more keen than he has been in the past to do a fifth series, set in the 1960s (centered around a rock band called the "Black Adder Five", with Baldrick — aka 'Bald Rick' — as the drummer) . However, aside from a brief mention in June 2005  there have been no further announcements from the BBC that a new series is being planned. Furthermore, in November 2005, Rowan Atkinson told BBC Breakfast News that although he would very much like to do a new series set in Colditz or another prisoner-of-war camp during World War Two, the chances of it happening are extremely low . There were a couple of ideas that had previously floated for the fifth series. Batadder was intended to be a parody of Batman with Baldrick as the counterpart of Robin (suggested by John Lloyd). This idea eventually came to surface as part of the Comic Relief sketch "Spider Plant Man" in 2005, with Atkinson as the title hero, Robinson as Robin, Jim Broadbent as Batman and Rachel Stevens as Mary Jane. Star Adder was to be set in space in the future (suggested by Rowan Atkinson).

June 2006, Rowan Atkinson (while filming French Bean in France) mentioned the possibility of a feature length version set during the Russian Revolution. Stephen Fry has expressed doubts over whether, since the series went out on such a good "high", a film would be a good idea.