The organ was built in 1961 and was one of the last completely new large instruments to be built by Compton before they focused solely on building electronic instruments which were also in production at the same time as this instrument was built. 

The organ is installed in 3 chambers in the west gallery and is said to be the loudest instrument in London. Unlike other instruments, this organ differed to what was the usual standard practice for Compton in that there is only one rank extended on each division and only the swell and choir divisions enclosed.

The specification reads:

Subbass 32'
Open Wood 16'
Open Metal 16'
Bourdon 16'
Salicional 16'
Dulciana 16'
Octave 8'
Flute 8'
Dulciana 8'
Flute 4'
Mixture III
Ophicleide 16'
Trombone 16'
Contra Posaune 16'
Tuba 8'
Clarion 4'

Contra Dulciana 16'
Violoncello 8'
Dulciana 8'
Gedackt 8'
Unda Maris 8'
Harmonic Flute 4'
Dulcet 4'
Nazard 2 2/3'
Piccolo 2'
Dulcet Fifteenth 2'
Tierce 1 3/5'
Acuta II
Clarinet 8'
Tuba 8' (unenclosed)

Double Diapason 16'
First Diapason 8'
Second Diapason 8'
Third Diapason 8'
Stopt Diapason 8'
Dulciana 8'
Octave 4'
Principal 4'
Twelfth 2 2/3'
Super Octave 2'
Fifteenth 2'
Mixture III
Double Trumpet 16'
Trumpet 8'
Clarion 4'

Contra Salicional 16'
Geigen Principal 8'
Salicional 8'
Lieblich Gedact 8'
Vox Angelica 8'
Gemshorn 4'
Salicet 4'
Zauber Flöte 4'
Fifteenth 2'
Mixture III
Contra Posaune 16'
Hautboy 8'
Cornopean 8'
Clarion 4'

COUPLERS (operated by luminous tabs above swell manual)
Swell to Pedal
Swell to Great
Swell to Choir
Swell Sub Octave
Swell Unison Off
Swell Octave
Choir to Great
Choir to Pedal
Choir Sub Octave
Choir Unison Off
Choir Octave
Great to Pedal
Swell Octave to Pedal

8 double touch thumb pistons to choir and pedal
8 double touch thumb pistons to great and pedal
8 double touch thumb pistons to swell and pedal
8 double touch toe pistons to pedal and great
4 general thumb pistons
8 collective thumb pistons
3 pedal coupler canceller thumb pistons
3 reversible thumb pistons
2 reversible toe pistons
1 general cancel thumb piston
4 ventil switches
1 balanced expression pedal to choir division with indicator
1 balanced expression pedal to swell division with indicator