At first the SED had a branch in West Berlin , but in 1962 the West Berlin branch was separated from the SED proper and became a `` separate '' party called the Socialist Unity Party of West Berlin ( Sozialistische Einheitspartei Westberlins - SEW ) . Initially the SED had a branch in West Berlin , but in 1962 that branch became a separate party called the Socialist Unity Party of West Berlin ( Sozialistische Einheitspartei Westberlins - SEW ) .