the mbw's headquarters were taken over by the london county council as its headquarters until county hall was built and occupied in 1922; the building was then renamed 'old county hall' and continued as a subsidiary office for the lcc until the original hundred-year lease on the site expired in 1958. it was subsequently used for central government offices and demolished in 1971 to make way for a new headquarters for the british council. the site is adjacent to admiralty arch, off the mall.