The Polish Social and Cultural Association (Polski Ośrodek Społeczno-Kulturalny, POSK) was born in 1964. It is the major socio-cultural institution of Polish diaspora in Greater London and United Kingdom. The origins of POSK date back to the arrival of Polish soldiers and civilians in Great Britain during World War II and their final settlement in 1945 when the majority of Polish émigrés chose not to return to communist-dominated Poland. POSK was the brain child of Roman Wajda (1901-1974), veteran of the Polish-Soviet War of 1920 and World War II, lecturer of the University of London and Polish University Abroad, social activist and community leader. The Association moved to its current headquarters in Hammersmith, London, in 1974. At present, POSK houses several institutions including the Polish Library POSK in London, Joseph Conrad Society (UK), Polish University Abroad, "Syrena" Theatre, art gallery, and Jazz Café.
From its creation in the 1960s, POSK actively opposed the communist regime in People's Poland; it staged plays and artistic events critical of communist ideology and supported anti-communist opposition. At the peak of its popularity in the 1960s, the Association had 3000 members, often veterans of the Polish Armed Forces in the West. The following decade saw the advent of activists born in Great Britain after World War II. Throughout its existence, POSK has cultivated ties with other centers of Polish diaspora in Europe and USA; after 1989, it has collaborated with cultural and educational institutions in sovereign Poland. Following Poland's entry into the European Union in 2004, the identity of POSK has been marked by the migration of thousands of Poles into United Kingdom.