Built in 1871 by Forster and Andrews of Hull, it suffered from severe woodworm attack and in 1985 only the casework, with its ornate diapason front pipes, together with five ranks of Forster and Andrews pipes could be salvaged. In 1986 Messrs Groves of Nottingham married these with a Gray and Davison organ from Chilwell in Nottingham. A detached console was sited to the east of the north aisle and the Bishop of Grantham dedicated the organ on 13th April 1986. It contains 818 separate pipes of which 456 are from the original organ. It is divided into three sections: the Swell Organ, the Great Organ and the Pedal Organ. The specification is as follows:
Great Organ Swell Organ
Clarabella 8' Lieblich Gedackt
Open Diapason 8' (F&A) Violin Diapason 8'
Principal 4' (F&A) Gemshorn 4'
Fifteenth 2' (F&A) Flageolet 2'
Trumpet 8' (F&A) Mixture 3 rank (F&A)
Pedal Organ Couplers
Bourdon 16' Swell Octave
Bass Flute 8' Swell to Pedal
Swell to Great
Detached Console Swell Octave to Great
2 manuals and pedals Great Octave
Stop tab operation Great to Pedal
7 thumb pistons, 6 toe pistons Tremulant
Balanced Swell Pedal
Electro Pneumatic action throughout.