The building was designed by the architect Mr F. A. Walters, and was built largely of red brick in the Dutch Jacobean style. The main outlines consist of a large central section running east-west, with two north-south wings projecting at either end. At the western end, the building continues beyond the wings to a large chapel, while at the eastern end there is a group of buildings housing resident domestic staff and the religious sisters who have supervised the housekeeping arrangements of the Seminary. This latter work was undertaken initially in 1899 by the ‘Daughters of the Cross’ and later, from 1951 to 1994, by the ‘Franciscan Missionaries of the Divine Motherhood’.
Facing the main entrance, the eye is drawn to the large entrance porch, with elaborate decoration in moulded and rubbed brickwork. At the top of the arch is carved, again in brick, the coat of arms of John Butt, the fourth Bishop of Southwark, who laid the foundation stone and blessed the building on 8th September 1891 , the cost of the building having been met by money raised by the previous Bishop, James Danell.
One of the most striking features of the Seminary is the Ambulacrum, an impressive open space 210 feet long and 19 feet wide, running the full length of the main section of the building at ground floor level. Immediately opposite the entrance porch is a shrine to the Blessed Virgin Mary, with the inscription ‘Queen of the Clergy, pray for us.’ This also serves as a memorial to Monsignor Philip Hallet, the longest serving Rector of St John’s . On the wall opposite the shrine, running from end to end, are the opening words of St John’s Gospel, ‘In the beginning was the Word, the Word was with God, and the Word was God. He was with God in the beginning.’
Due to a steady increase in numbers during the 1950s, plans were made to increase the available accommodation. This work, begun in 1960, extended the wings of the building to twice their original size. The chapel was also lengthened at about the same time. To some extent, the extension of the wings disturbed the original proportions of the building as seen from outside. Nevertheless, there were advantages apart from the purely practical. The refectory, running the length of the south-east wing at ground floor level, has a much more open feel than previously, ending in a beautiful large window at the south side. When the sun shines, and the room is laid out for a large gathering of people, it is a fine sight.
The ‘Philosophy Room’, occupying a similar position on the south-western side, is also a very pleasant room, with its large south-facing window and well-balanced proportions. Its name derives from the time when those in their first two years of study had lectures all together in various branches of philosophy, in this room. The similar room in the north-west wing, which was used for theology lectures for those in their final four years of study, is now divided into offices and a smaller ‘Conference Room’. On the opposite side, on the ground floor of the north-east wing, lies the ‘Upper Common Room’, used for a variety of gatherings, including occasional theatrical productions which make use of the stage at the north end. The library, on the first floor above the refectory, has the advantage of an attractive appearance and some interesting decorative woodwork, but the disadvantage of being a cold place to work in winter, despite thermal insulation of the roof space and improvements in the central heating!
In 1986 St John’s was placed on the statutory list of buildings of architectural and historical importance.
The chapel is dedicated, not to the Seminary patron St John , but to the Sacred Heart. It was built in 1895 with money donated by Mr and Mrs Broderick of Brighton , and has the unusual feature that (for practical reasons) the altar is at the west end of the nave. Above the entrance to the chapel, a Latin inscription reads ‘The Master is here and he is calling you’ (words of Martha to her sister Mary in John 11:28 ). The Solemnity of the dedication of the Chapel is kept on 5th May each year.
On entering the chapel, the Lady Chapel is on the right, the ante-chapel or Narthex on the left, while straight ahead there is a passage leading to a series of side-chapels dedicated respectively to the English Martyrs, St Francis de Sales, St Charles Borromeo and, finally, St John. At one time, when segregation of students was more strict, the public were restricted to the ante-chapel area. Here there is a statue to St Joseph , patron of the universal Church. The screen separating this area from the main body of the chapel runs up to the organ gallery.
In the centre of the nave, there is a stone marking the burial place of Bishop Butt, the founder of the Seminary. In niches on the south side are statues of St Simon Stock, St Cyril of Alexandria and St Anselm. On the opposite side are statues of St Bernard of Clairvaux, St Cuthbert Mayne and St Bede.
In 1961 the chapel was extended at the western end, moving the altar to a position beneath the gold mosaic which originally served as a backdrop for a large wooden crucifix. At the same time, the three stained-glass windows were added, representing Our Lady, St Joseph and St John .
By the mid 1980s, the chapel was in need of certain internal repairs and re-wiring, and the opportunity was taken to re-order the layout to a certain extent, reflecting changes in the liturgical practice of the Seminary following the revisions of the Second Vatican Council. This work was begun in 1989 and completed the following year, the architect being Mrs Corinne Bennett of Winchester . In place of the high altar, a marble pedestal was constructed, on which the tabernacle now stands, and a wrought-iron screen was erected on a line separating the chapel extension from the original body of the chapel, so that the extension now serves as a Blessed Sacrament Chapel. A new altar was built between the screen and the present four rows of choir benches, using the mensa from the original high altar. At the same time, a roughly semi-circular row of benches was added between the altar and the screen, for concelebrating priests.
Following the tradition of including a cross or crucifix prominently within the sanctuary area, it was decided to commission a sculpture on this theme, to be mounted on the top of the screen. The result, designed by Mrs Faith Tolkien, is based on a mosaic in the church of San Clemente in Rome . It depicts Christ upon the cross, after the moment of death. Water is shown flowing from the base of the cross, calling to mind the text ‘from his side flowed both blood and water’ (John 19:34 ), symbolising the sacramental life of the Church, and reflecting the chapel’s dedication to the Sacred Heart. The stags suggest the relation of the Christian to Christ, hinting at the passage in Psalm 42: ‘as the deer yearns for running streams, so my soul is thirsting for you, my God.’
The installation of a refurbished Willis Organ was completed in 2005. This historical 1866 mechanical action instrument was previously in St Mark’s Church, Horsham.