Foe

recalled that the Third Doctor was a "worthy" foe. (GAME: Destiny of the Doctors)

MP David Lloyd George famously declared that Britain had three enemies: "Germany, Austria and Drink; as far as I can see, the greatest of these three deadly foes is Drink." His attempt, as Chancellor of the Exchequer, to ban alcohol entirely led to the introduction of licensing laws to increase taxes on alcohol and to restrict its sale and the opening hours of public houses. In private, however, (PROSE: The Time Traveller's Almanac) he drank the Ninth Doctor under the table. (TV: Aliens of London)

Behind the scenes
The Seventh Doctor regarded the Zarbi as his foes. (NOTVALID: Doctor Who? 139)