Equity and other causes
In 1929, at the age of seventeen, he became a founding member of British Equity, the actors' union, and would be intricately involved with it for the rest of his professional life.
He served on its council from 1949 and was three times its vice president from 1963 to 1965, 1975 to 1977 and again from 1980 to 1982.
Goring's relationship with his union was fraught with conflict and, as an influential and conservative member of the union he waged battles in the 1970s with such left-leaning members as the Redgraves: Vanessa and her brother Corin. He did not want union funds being contributed to causes such as the Miner's Strike fund as he viewed that as sacrificing its neutrality. He believed that, above all, the union's focus should always be on the welfare of its members and that it should not get involved in political causes.
These fights became increasingly vitriolic and quite bitter at times, often waged through the editorial pages of The Times and The Stage newspapers. Marius was a frequent writer of Letters to the Editor of The Times about union matters and on a number of other subjects on which he had an opinion.
He even took his union to litigation on three occasions. In the longest running case, regarding the issue of the supremacy of a referendum to decide Equity rules, he took it as far as the House of Lords in 1978 and won his case.
However, in 1992, he unsuccessfully sought to end the restriction on the sale of radio and television programmes to apartheid South Africa. This particular litigation nearly bankrupted him, due to the heavy amount of court costs.