The heart of the Hall is the vast internal auditorium 185 feet wide by 219 feet long covered by a glazed dome constructed of wrought iron girders which, at the time, was the largest structure of its kind in the world
Other notable features include the Great Henry Willis Organ also, at the time, the largest in the world and, in tribute to its power and volume, described by a contemporary as 'The Voice of Jupiter'. Between 1921 – 1933 it was substantially modified and enlarged by the Durham-based organ firm of Harrisons and it was comprehensively restored by the London firm, Manders, between 2003 – 2004.