After Malta was granted self-government in 1921, the auberge was converted into a school. In 1924, upon Ugo Pasquale Mifsud's election as Prime Minister of Malta, the building became the Office of the Prime Minister (OPM). In 1931, there were plans to move the parliament from the Grandmaster's Palace into the auberge, but nothing materialized. The building continued to house the OPM until the office was abolished upon the suspension of the constitution in 1933. From 1933 to 1939 the building was left vacant. In 1939, the auberge was given to the British Institute. It was used as a hospital for British families during WWII known as the Military Families’ Hospital.