Christopher Naylor

 was a voice actor who portrayed several roles in Big Finish audio stories, notably recreating the role of companion Harry Sullivan.

Audio roles
As Harry Sullivan

The Lost Stories

 * Return of the Cybermen

UNIT: Nemesis

 * Fire and Ice
 * The Curator's Gambit

Other Roles

Doctor Who Main Range

 * Black Thursday - James Hudd
 * The Kamelion Empire - Alternative Kamelion / Chaos Soldier

The Lost Stories

 * The Doomsday Contract - Villager

The Fourth Doctor Adventures

 * The Perfect Prisoners - Malpha / Sentreal / Trooper / Worker
 * Chase the Night - Bolan
 * The Tribulations of Thadeus Nook - Krillian / Cop / Halder

The Eighth Doctor: The Time War

 * The Lords of Terror - Guard
 * Planet of the Ogrons - Ogron

The Tenth Doctor Adventures

 * One Mile Down - Pickus

The First Doctor Adventures

 * The Great White Hurricane - Policeman / Man with Ladder / Gang Member / Henry
 * The Barbarians and the Samurai - Captain Hamilton

The Diary of River Song

 * Whodunnit? - Lord Simon Whist / Captain Bartholomew / Discordia Underling
 * The Lifeboat and the Deathboat - Number Two / Computer / James