Warning! SPOILERS for the Doctor Who Centenary Special, The Power of the Doctor.
The script for the Doctor Who 60th Centenary special, "The Power of the Doctor," has been published by the BBC, and it reveals that Chris Chibnall almost brought back an unexpected companion in Jackie Tyler. After the episode's climax, in which both Jodie Whittaker's Doctor and Sacha Dhawan's Master were severely injured by the creature who powered the Cyber-planet, the Doctor had left Yaz on earth so she could regenerate by herself. Yaz soon discovered that she was not alone, however, as Graham had started a support group for former Doctor companions across his many regenerations.
The ending of "The Power of the Doctor" is heartwarming, with Graham, Yaz, and classic-era Doctor Who companions including Bonnie Langford's Mel (Sixth and Seventh Doctor companion) finding a new family in one another to fill in the hole the Doctor left in their lives. In Chibnall's script for the Centenary special, he writes that he wanted to bring back relaunch-era companions for this scene as well, "On a laptop screen we might even see a few others joining in: Martha or Ryan or Jackie Tyler!" This would have been a controversial storytelling decision, not least because Jackie as Rose's mum settled down in a parallel dimension at the end of season 2.
Should Jackie Tyler Be Considered A Doctor Who Companion?
To describe the Chibnall era of Doctor Who as flawed would be an understatement. From its focus on nostalgia bait, to over-simplistic storylines, to the infamous timeless child revelation that retconned the show's core concept. Including Jackie, Rose's mum, as a Doctor Who companion might not have been the most contentious issue across Chibnall's three seasons, but it would have incited debate, despite her being an important character in the canon. Over the first two seasons of the relaunch era Jackie featured more frequently than most companion family members, and she returned to the original universe with Rose and Mickey for season 4's two-part finale and Russell T Davies-era culmination.
But presenting Jackie as a bona fide companion arguably undermines the gravity of what that role means. The adventures true Doctor Who companions go on, and the intimacy with which they get to know both the Doctor and themselves through the beauty and horrors across time and space, transform them into singular, special characters. During seasons 1 and 2 there is even friction between Rose and Jackie because the latter struggles to understand how these adventures have so dramatically changed Rose.
How Would Jackie Tyler Dial Into This Meeting?
Given Jackie exists in a parallel dimension which the Davies era went to great pains to present as being practically impossible (and dangerous) to tamper with, Jackie would find it difficult and irresponsible to break the laws of the universe for a friendly catch-up. If they were to introduce her via a laptop to the companion support group as Chibnall suggests, it is hard to see how it could mechanically make sense beyond the classic "timey-wimey" justification, as the writers occasionally do when the science in Doctor Who's Sci-Fi threatens to overcomplicate its fiction. Maybe the parallel dimension has excellent fiber-optic broadband for that Zoom connection.