Sergeant (Ascension of the Cybermen)

In the Matrix-constructed story behind which hid the true fate of the Timeless Child, (TV: The Timeless Children) a sergeant admitted Brendan into the Garda. (TV: Ascension of the Cybermen)

Behind the scenes
In Chibnall's post-production script, the sergeant was named Michael. In the credits of the broadcast episode, however, Michael is instead the name given to the thief who shoots Brendan. (Neither the sergeant nor the thief are ever named in dialogue, either in the script or the episode.)