Denis Carey (3 August 1909 – 28 September 1986) was a British actor who appeared in many film and television roles, although his biggest box office success was the revue Salad Days, which ran for 2,283 performances in the 1954–55 London season. He was married to actress Yvonne Coulette.
Some of Carey's notable appearances include Dennis Potter's 1968 television series A Beast With Two Backs, Elizabeth R, I, Claudius and The Barchester Chronicles. Carey appeared three times in the BBC science fiction series Doctor Who, including Professor Chronotis in the incomplete serial Shada, as the eponymous Keeper in The Keeper of Traken, and as the fake old man Borad in Timelash.
Biography from Wikipedia, CC BY-SA. Credits and photos from TMDB.
The titles people know Denis from.
IMDb rating of each title on Cineora, by year.

as Professor Chronotis (archive footage)

as Professor Chronotis
as Mr. Lamb

as Wally

as Old Man

as Ted

as Skulpit · 2 episodes
as Dr. Jordi Casals · 2 episodes

as The Keeper

5 episodes

as King Pelles · 2 episodes
as Docholli · 1 episode

as The Colonel · 1 episode
as Mr. Spanier
as Livy · 1 episode
as Casson

as Doctor, at The Spike

as Ebenezer

as Barrington · 1 episode
as Private Attercliffe · 3 episodes

as Sir John Mounson

as Yates · 1 episode
as The Keeper · 1 episode

as Mr. Dinsdale

as Pte. Attercliffe

as Father Ryan · 1 episode
The people who keep turning up in Denis’s titles.