Leszek Kolakowski, who has died in Oxford at the age of 81, enjoyed the peculiar distinction of being an outstanding academic philosopher who provided intellectual inspiration for the overthrow of communism in his Polish homeland.

He began adult life as a convinced Marxist, joining the Communist Youth Organisation in Poland in 1945, but changed his thinking progressively through Marxist humanism to become a rigorous critic of communism and, having fled Poland in 1968, a leading European liberal intellectual. As a specialist in the history of religion, he returned to a belief in Christianity, although his thinking was always tempered with tolerance and scepticism at any hint of excessive fundamentalism.