In 1978 Bush retired from the RAM after 52 years' service. His 80th birthday in December 1980 was celebrated at concerts in London, Birmingham and East Germany, and the BBC broadcast a special birthday musical tribute. In the same year he published "In My Eighth Decade and Other Essays", in which he stated his personal creed that "as a musician and as a man, Marxism is a guide to action", enabling him to express through music the "struggle to create a condition of social organisation in which science and art will be the possession of all". In 1982 Bush visited the Lascaux caves in south-western France, and was inspired by the prehistoric cave paintings to write his fourth and final symphony, Op. 94, subtitled the "Lascaux". This, his last major orchestral work, was premiered by the BBC Philharmonic Orchestra, under Edward Downes in Manchester, on 25 March 1986.