Architectural Features
The C12 3 stage tower has 2 chamfered string courses, a single clasping buttress to south west angle
C15 ashlar belfry stage with battlemented parapet having quatrefoil frieze, gargoyles and paired cusped louvred lights in hollow chamfered surrounds.
Several of the gargoyles on this church have been mutilated by later drain installation. This one on the top of the tower has not.
The north aisle wall of ashlar is late C13 having chamfered pointed doorway with to west a quatrefoil and to east a 3 light window with Geometric roundels and beyond a further 3 light window with intersecting tracery.
The aisle was lengthened in the C15 and 2 three light windows with cusped heads and 4 centred chamfered surrounds were added.
The C15 south aisle has a single 3 light east window and 3 similar south windows, all with cusped heads to the lights and moulded 4 centred arched surrounds.
The C14 2 storey south porch has a pointed outer arch with shafted reveals and moulded hood.
The C14 inner doorway is moulded and pointed with hood.
Late C14 4 bay nave arcades with clustered annular shafts, engaged octagonal capitals, moulded arches and hoods.
The tall C14 tower arch has moulded reveals, annular moulded hood with florate stops.
The C13 double chamfered chancel arch, dying to the reveals, has beside it the doorway to the rood loft.
In the south aisle is a reset C14 embattled statue bracket and a fine double piscina having cusped canopies and pinnacles.
In the north wall of the chancel are 2 C15 moulded arches to the north chapel and 3 C19 arched openings in the Sanctuary.
On the walls of the nave and aisles is an extensive scheme of C14
early C15 wall painting including scenes of King Herod, Magi, Virgin and Child, St. Anne teaching the Virgin, a gigantic St. Christopher.
Detail of painting, including a Devil. This demon draws the eye from all the rest of the paintings, somehow. The style might be called 'naive' by modern artistic standards, but it has huge presence.
In the quatrefoil north aisle window is a C15 stained glass figure and other fragments of medieval glass are in other windows.
Medieval wall painting of Shepherd and sheep, and a sheepdog. This seems a most appropriate image for Corby Glen which has just hosted its 775th sheep fair
Near the south door is a C15 iron bound oak chest.
C17 turned baluster altar rails.
The C13 font has an octagonal bowl with stop chamfers to the square base which is now supported on a free standing marble shaft added in 1893.
The font and cover at St Johns. The 13th-century octagonal font was re-mounted on marble pillars in 1893. Behind the font on the wall is the old medieval weather vane.
Monuments.
In the north chapel an oval monument with elaborate roccoco surround to Frances Wilcox d. 1764, and in the north aisle are 3 other C18 wall plaques by Hawley of Colsterworth having fine ribbon work and classical flourishes.