The western gallery is dominated by the organ-case. Of this the three central towers with the "flats" between are the original case installed by Gerald Smith, nephew of the builder of the St. Pauls Cathedral organ, Bernard Smith. It was completed in 1725, contained 1514 pipes, and had three manuals, Great, Choir and Swell. The cost was £500. In 1761 the Parish Vestry contracted with John Snetzler for a new organ to be fitted into the old case, for which he was to have £300 and the old pipes. A further rebuilding was undertaken by J.C. Bishop in the early 19th century.
The instrument had no pedal board until its renovation and enlargement by William Hill in 1864 at a cost of £440. In 1894 the Hope-Jones Electric Organ Company completely rebuilt and enlarged the organ. Sir Arthur Blomfield was responsible for the additions to the case. A fire in 1896 severely damaged the instrument and it had to be almost completely rebuilt. The present organ was built inside the old case by Harrison and Harrison of Durham in 1972 with the addition of the small "chair" organ above the Royal Arms and a console in the north gallery. The Hope-Jones console is still to be seen on the south side of the choir.
