Maxil

Commander Maxil was a member of the Chancellery Guard. Zealous and humourless, he stunned the Doctor and confined him in a cell under the Capitol to await the judgment of Lord President Borusa and the High Council of Time Lords. (DW: Arc of Infinity) He was promoted to Castellan briefly after the death of Andred, but after siding with Pandora and Inquisitor Darkel in the Civil War was demoted back to Commander. (BFG: Appropriation)

Coincidentally, Maxil looked very similar to what the Doctor looked like in his sixth incarnation.

Behind the Scenes
Maxil was portrayed by Colin Baker, who later became the Sixth Doctor. As a result of Baker being chosen to replace Peter Davison as the Doctor, the character of Maxil was dropped from the later anniversary story The Five Doctors.

Colin Baker has said he made the suggestion that, in DW: The Mysterious Planet, Commander Maxil should have arrested the Doctor and taken him into the trial room.

This wasn't the last time a future Doctor would be involved in an earlier production; David Tennant participated in several Doctor Who audio productions for Big Finish (the first being BFA: Colditz) before being cast as the Tenth Doctor.