The nave has 7 bays: the most western is Victorian but the other 6 are 15th century with tall pointed arches. The present panelling was completed in 1962. Lord Grimthorpe also altered the clerestory by inserting larger windows. The south aisle is 15th century and has tall three-light windows with the original stone tracery still intact. The north aisle, rebuilt in 1893, also has three-light windows in keeping with those of the south aisle. They were probably designed by Lord Grimthorpe.
The Woodwork The hexagonal oak pulpit executed by J. A. Goyers in 1863, is an excellent example of wood carving, having figures of the Evangelists in four of the niches and vine leaves and grapes below the hand rail. All other woodwork is 20th century.
The Hassocks Traditional heraldic treatment has been given to the designs which include the Sees of Canterbury, Lincoln and Rochester as well as County and Parish organisations and personal associations of Parish members.
Brasses and tablets St. Peters has lost all but one of the many brasses laid down in the medieval period. The one remaining, now on the wall near the south door, is to Roger Pemberton, who was High Sherrif of Hertfordshire in 1620. In the porch is the portion with the inscription, lost during restoration and found in 1934. It was found to be a palimpsest (i.e. a monumental brass turned and re-engraved on the reverse side) (twice used) with an earlier inscription on the other side.
The best monument now remaining in the church is on the east wall of the north aisle. It is to Edward Strong, Sir Christopher Wren's master mason at St. Paul's Cathedral. Nearby is the memorial to Lieut-Col. William Dobbins who died in 1738. In the chancel is a memorial to the Rcvd Horatio Nelson Dudding who was Vicar of St. Peter's for fifty-three years. He died before the renovations were complete and the chancel had to be cleared of building materials so that the funeral could take place.
The Glass Very little of the medieval glass has survived the Reformation and the Civil War. Surviving fragments are mounted in the windows of the north aisle. The portrait of a 15th century abbott and a pelican can be seen, the latter is Victorian. The rose window over the west door was designed by Lord Grimthorpe and the coloured glass inserted in 1922. The windows in the south aisle, depicting the parables, by Capronnier, (a Belgian artist) were installed between 1863 and 1872. The east window is early 20th century.
||View of church interior looking towards west end, showing the new glass doors and the rose window, put in by Lord Grimthorpe in the last century.
The Lady Chapel is in the two eastern most bays of the south aisle. The Lady Altar is moved into the nave for the Sunday morning services.