Sergeant (The Five Doctors)

From Tardis Wiki, the free Doctor Who reference

A sergeant was on Colonel Charles Crichton's UNIT staff at the time of the Brigadier's retirement. (TV: The Five Doctors)

Behind the scenes

This sergeant was originally meant to be Benton, but John Levene declined because in the script he would have to not recognise the Second Doctor. Levene thought that Benton would have remembered that version of the Doctor and not made such a mistake.