The organ has an interesting story. It was built by Compton in 1930 as job number A116 and thought to have been installed at the Convent Church of the Sacred Heart in nearby Newhaven particularly as St Pancras Church did not get built until 1939. The Convent closed in 1943 and so it is thought that the organ was moved here to Lewes probably in the late 1940s or early 1950s. The organ is installed in a fully enclosed chamber at the front of the church on the left with the console in the rear gallery.

Of particular interest is that the console is of a very similar design to that of the cinema instruments which Compton were installing at this time.

The specification reads:

Sub Bass 32'
Sub Bass 16'
Salicional 16'
Salicet 8'
Flute 8'
Trombone 16'
Great to Pedal
Swell to Pedal

Bourdon 16'
Contra Salicional 16'
Diapason 8'
Viola da Gamba 8'
Salicional 8'
Hohl Flute 8'
Octave 4'
Salicet 4'
Flute 4'
Twelfth 2.2/3'
Fifteenth 2'
Acuta II
Trumpet 8'
Swell to Great

Contra Viola 16'
Viola da Gamba 8'
Salicional 8'
Vox Angelica 8'
Hohl Flute 8'
Viola 4'
Salicet 4'
Vox Angelica 4'
Flute 4'
Fifteenth 2'
Cymbale III
Trombone 16'
Trumpet 8'
Clarion 4'

4 double touch thumb pistons to Great and Pedal
4 double touch thumb pistons to Swell and Pedal
4 toe pistons to Pedal
1 canceller thumb piston - Great to Pedal
1 canceller thumb piston - Swell to Pedal
1 balanced expression pedal - organ
1 balanced expression pedal - crescendo
Double touch canceller to each department
6 ventil switches