Karlin, who was best known for playing militant shop steward Paddy in 1960s TV sitcom The Rag Trade, was a passionate political activist on behalf of a number of left-wing causes including actors union Equity.
Born in 1925 and a graduate of RADA, Karlin made her London stage debut in The Time of Your Life at the Lyric Hammersmith in 1946.
Her stage credits include the 1956 production of The Diary of Anne Frank at the Phoenix theatre and Theatre Royal Straford East's Fings Ain't Wot They Used T'Be, which transferred to the West End's Garrick Theatre. She played Lilly Smith in Lionel Bart's East End play with music for two years. She subsequently appeared in a series of plays by Saul Bellow, staged in London in 1966.
A member of the Royal Shakespeare Company in the 1970s, she appeared alongside Laurence Olivier in the film version of The Entertainer and also starred alongside Chaim Topol, Alfie Bass, Lex Goudsmit and Barry Martin as Golde in the 1967 West End debut of the musical Fiddler on the Roof at Her Majesty's Theatre.
Karlin campaigned on behalf of Anti-Nazi League, CND and Soviet Jewry and was a council member of Equity - she was awarded an OBE in 1975 for her union and welfare work. In 2008, at an Equity meeting at the Young Vic, she called for a vote of no confidence in proposed Arts Council England cuts.
Equity spokesman Martin Brown said today: "She was a wonderful actress, an absolutely indefatigable campaigner and a marvellous friend. We will miss her enormously."
Karlin continued working into her 80s, her recent television credits including Casualty, The Bill, Miss Marple and Holby City. Her film work including A Clockwork Orange, Room at the Top, Mahler and So Haunt Me as well as 2006 feature Children of Men where she appeared alongside Daniel Craig.