A good view of the outside of the church can be seen from the churchyard garden on the north side, where a path leads diagonally across to steps leading to the church hall. Looking back, one can see the buttresses and walls which are of mixed rubble with septaria, flat Roman brick and ragstone. The parapet of the north wall has diapering with carved rosettes; on the east wall are two shields, one a chevron with a molet and the other has a cross. Also, in the north wall in the fourth bay, are traces of a 15th century doorway with a two centered head.
The west tower was erected in 1758 when the central tower was demolished. It is a red brick structure with white brick quoins and battlements.
The clock was added to the tower in 1866, originally flat against the wall and later placed on its present heavy stone bracket. The hours were struck on the tenor bell in the tower and the quarter chimes on smaller bells but the chimes were later silenced to avoid confusion with the striking of the clock on the town hall.
A charnel house - a brick built vaulted underground structure for depositing bones found in the churchyard - exists at the north-east corner, but only the steps leading down to the entrance of what is now a boiler house are visible. It was built in the early 16th century when the vestry above it was added to the church.
An ancient doorway will be found at the west end of the south wall. This doorway is now blocked up on the inside of the aisle wall and can only be viewed from the churchyard. The wrought- iron scroll work on the door is particularly fine and has been attributed to the late 13th century and the work of Thomas de Leighton, but it is now thought that this may not be the case.
In the south churchyard an iron gateway leads out to the High Street, and the site of the former Vicarage house of St Peter's, now the Co-operative Bank. The present Vicarage is situated at the end of Balkerne Close, the entrance to which is opposite the back yard of the "Pat Molloy's" public house (previously known as O'Neill's and before that as the Waggon & Horses). The Vicarage was built in 1960 in the garden of the previous Vicarage, 59 North Hill, which itself was bought in 1842 when the original one in the High Street was destroyed by fire.