The Radio Theatre (formerly the BBC Concert Hall) has in its 'front' wall a cavity roughly 40ft. wide by 30ft. high, and only 6ft. from front to back; it opens into the theatre via a central ornamental grille about 15ft. square. This was the location in which the John Compton Organ Company installed an extension concert organ in 1933. There are 33 ranks, 123 stops and 2,478 pipes. There are three expression chambers (Great, Swell, Choir) with a few basses unenclosed. The console has Compton's luminous push-button stops.

GREAT
     16      Double Diapason
      8      First Diapason
      8      Second Diapason
      8      Stopped Diapason
      8      Gemshorn
      8      Salicional
      4      Octave
      4      Zauber Flöte
      4      Gemshorn Octave 
     2 2/3   Twelfth
      2      Fifteenth
      2      Super Octave
     IV      Pleinjeu  12.15.19.22
     IV      Petite Cymbale  19.22.26.29
     16      Contra Tromba
      8      Tromba
      8      Horn
      4      Tromba Ottava
 
SWELL
     16      Contra Viola
      8      Geigen
      8      Rohr Gedeckt
      8      Viola da Gamba
      8      Vox Angelica
      4      Geigen Octave
      4      Gedeckt Flöte
      4      Viola
      4      Vox Angelica
      2      Super Octave
      2      Sifflöte
     III     Cornet  15.19.22
     III     Cymbale  22.26.29
     16      Double Hautboy
      8      Trumpet
      8      Hautboy
      4      Clarion
      4      Hautboy Clarion
             Tremulant
 
CHOIR
     16      Violone
     16      Double Dulciana
     16      Lieblich Bordun
      8      Violoncello
      8      Viola Acuta
      8      Viola Celeste
      8      Dulciana
      8      Flauto Traverso
      8      Lieblich Gedeckt
      8      Echo Flute
      4      Violino
      4      Dulcet
      4      Flauto Traverso
      4      Lieblich Flöte
      4      Echo Flute
     2 2/3   Dulcet Twelfth
     2 2/3   Nazard
      2      Dulcet Fifteenth
      2      Kleine Flöte
     1 3/5   Tierce
     II      7th & 9th  21.23
     III     Echo Cornet  15.19.22
     16      Double Clarinet
      8      Clarinet
      8      Oboe
      8      Vox Humana
      4      Musette
      8      Tuba Mirabilis
             Sustainer
             Tremulant
 
SOLO
      in Great chamber:
      8      First Diapason
      8      Zauber Flöte
      8      Concert Flute
      4      Stopped Flute
     IV      Cornet  12.15.19.22
     16      Double Horn
      8      Horn
      4      Octave Horn
     16      Contra Tromba
      8      Tromba
      4      Tromba Ottava
      in Choir chamber:
     16      Contra Viola
     16      Contra Viola Celeste
      8      Violoncello
      8      Viola Acuta
      8      Viola Celeste
      8      Dulciana
      8      Flauto Traverso
      4      Viola Ottava
      4      Viola Ottava Celeste
      4      Flauto Traverso
      2      Flauto Piccolo
      8      Basset Horn (synthetic compound)
      8      Kalophone (synthetic compound)
     16      Fagotto
      8      Clarinet
      8      Oboe
      8      Vox Humana
      4      Vox Humana
      8      Tuba Mirabilis
      4      Tuba Clarion
             in Swell chamber:
      8      Viola da Gamba
      8      Vox Angelica
      8      Cor de Nuit
      4      Quintaten
     16      Double Trumpet
      8      Trumpet
             Sustainer
 
PEDAL
     32      Sub Bass (polyphone)
     16      Contrabass
     16      Diapason
     16      Sub Bass
     16      Violone (Choir)
     16      Viola da Gamba (Swell)
     16      Dulciana (Choir)
      8      Octave
      8      Flute
      8      Gedeckt
      8      Violoncello IIIrks (Choir)
      8      Dulciana (Choir)
      4      Flute Octave
     IV      Fourniture  12.15.19.22
     16      Bass Hautboy (Swell)
      8      Hautboy (Swell)
     16      Bass Clarinet (Choir)
      8      Clarinet (Choir)
     32      Contra Trombone
     16      Ophicleide
     16      Trombone (Great)     
      8      Tuba      
 
 
Couplers: 10 unison - n.b. Great to Choir, no Choir to Great.
          Pedal to Choir.
 
Thumb pistons: 10 departmental to each manual and pedal, 8 general.
               32-channel solid-state capture system installed 1992 
               (replacing the original 2-channel electro-mechanical system).
               One 'pedal' piston to each manual giving suitable pedal bass.
               Reversibles to the ten unison couplers.
               Setter.  General cancel.               
 
Toe pistons:  5 each to Swell, Great, Pedal.
              Reversibles to Swell to Great, Great to Pedal, 32ft. Sub Bass, 
                             32ft. Contra Trombone, Solo & Choir Sustainers.
 
9 luminous stops to select Great-Swell-Choir boxes on shoes 1-2-3.
 
Switches:  4 - Pedal organ on manual 2nd-touch Solo-Swell-Great-Choir.
           Cancellers off.   Great unenclosed (fixes shutters open).
 
Balanced pedals: 3 to expression chambers, 1 general crescendo.
 
Compass: 61/32.

SOURCE:
Organ Club meeting notes, 22 January 2000.