TV Century 21 or TV21 was an English publication printing articles and tie-in comic strips to popular children's adventure series. It was published throughout the 1960s.
Each issue of TV21 passed itself off as a news magazine printed exactly one hundred years in the future. It mainly featured comic strip stories based on the puppet television creations of Gerry Anderson, although it also featured the stories later known as The Dalek Chronicles. The Doctor (at that time played by William Hartnell) did not appear in these stories as the rights to the character were with Polystyle Publications, Ltd., the publishers of TV Comic; TV21 didn't want to use the Doctor anyway as the strip was about the Daleks. Apart from this feature, TV Century 21 did not feature any other substantial Doctor Who content.
However, a record, simply entitled The Daleks came out, containing the soundtrack to "The Planet of Decision", the last episode of The Chase, was released as a TV 21 record, with narration by David Graham (one of the Dalek Voices) to explain plot points less obvious without any visuals.
After the Daleks' comic strip had ended, the Doctor's arch-enemies would, as they had on television, make appearances as villains in the TV Comic Doctor Who stories. Indeed, in their first appearance in TV Comic, The Trodos Ambush, the Daleks landed on Trodos and massacred the Trods, having found out that the Second Doctor was on his way there in the hope of signing a peace treaty with the Trods.