[1][2][3] The party was founded by Ignacio Camuñas in December 1974 on the basis of the Circle of Studies New Generation (Spanish: Círculo de Estudios Nueva Generación), created in 1972.
[8] Fernando Chueca Goitia, founder of the Spanish Social Democratic Union (USDE), left the party in July 1976 to join the People's Democratic Party, where he was elected president in December of that year.
[2][3] The party was admitted as a member of the Liberal International during the Congress that took place in Barcelona in October 1976;[6][9] also, the PDP participated in the creation of Union of the Democratic Centre (UCD) in 1977, forming the liberal wing of UCD.
[10] In the general elections of 1977 the party obtained 6 deputies within UCD: Ignacio Camuñas, José Manuel Paredes Grosso, Francisco Ruiz Risueño, Manuel Bermejo and José María Bravo de Laguna.
[11] Subsequently, on December 16, 1977, the party agreed to dissolve and become a full member of UCD.