Porter was one of London's great stage actors of the mid-20th Century. Starting in the early 1940's, Porter gained a reputation as a reliable and competent professional actor.
A respected Shakespearean, he built a solid resume with parts in Troilus and Cressida, Volpone, Cymbeline, The Two Gentlemen of Verona, Macbeth, Hamlet, The Merchant of Venice, The Visit, and most famously King Lear.
He was a regular fixature in British television- World Theatre, BBC Sunday Night Theatre, Theatre Night, The Last Invitation, The Forsyte Saga, Anna Kerenina, Churchill and the Generals, Why Didn't They Ask Evans?, Hamlet Prince of Denmark, Little Lord Fauntleroy, The Crucible, Winston Churchill: The Wilderness Years, The Jewel in the Crown, Oliver Twist, and as Professor Moriarty in The Adventures of Sherlock Holmes.
His film acting was more ensemble pieces- Town on Trial, The Fall of the Roman Empire, The Pumpkin Eater, The Heroes of Telemark, Kaleidoscope, The Lost Continent, Hands of the Ripper, Nicholas & Alexandra, Antony & Cleopatra, Hitler: the Last Ten Days, The Day of the Jackal, The Belstone Fox, Callan, Hennessy, and The 39 Steps.
Sadly, Porter is almost forgotten about in the list of great theatrical titans of the 20th Century.