RCHME survey. The N. gatehouse is of two storeys, the walls are partly of rubble and partly of brick with limestone dressings; the roofs are covered with lead and tiles. It was built probably in the 15th century and has been considerably restored.

Elevations- The north front has a moulded plinth, modern parapet and walls faced with knapped flint set in stone panels with cusped heads; this work is mainly original to the ground storey and mainly restored to the upper storey; the restored work includes a series of lily-pots in stone. Flanking the gate are two octagonal turrets of two stages with ornamental cresting, partly restored between the stages and crocketed pinnacles restored at the top. The main outer archway has stop-moulded jambs and four centred arch of two orders with a moulded label and a square-headed outer label with defaced carved spandrels; the small archway further west is similar but without labels or spandrels; flanking the main arch are two large niches with trefoiled and crocketed canopies, semi-octagonal on plan and each having a ribbed lierne vault with a central rosette and small supporting shafts in the angles; the brackets are moulded and supported by large half-angels holding shields, that on the east with the Agnus Dei and that on the west defaced; flanking the niches are shallow buttresses.

The upper storey has two windows all modern except the lower part of the jambs of the eastern window; between the windows is a large niche almost entirely restored. The front of the porter's lodge adjoining the gatehouse on the east has a moulded plinth and remains of the junction of a thin wall extending towards the north. Further east are remains of original windows with a square head, subsequently used as a doorway and now blocked with bricks. The south front has an inner archway with stopped jambs and four-centred arch of two hollow-chamfered orders with a moulded label and head-stops and partly restored. Above it is a window almost entirely modern and the parapet is also modern. The octagonal turrets are finished with crocketed pinnacles.

The Gate Hall has a ribbed lierne vault of stone with moulded ribs and ashlar web; at the middle intersection is a defaced carved boss; the ribs spring from moulded corbels carved with two human heads and two lions, one of them winged; in the north east angle are marks of the impact of a cannon ball, probably dating from the period of the siege in 1648. In the east wall is a doorway with stop-moulded jambs and four-centred head. In the west wall is a recess with moulded jambs and four-centred head and further S. is a doorway with similar mouldings and head. The porter's lodge, now of two storeys with attics, has no ancient features internally. The rough south wall seems to indicate that if formerly extended further in that direction. Adjoining the west side of the gatehouse was a building now destroyed; from it the staircase in the south west turret was entered and has two doorways one above the other, each with a four-centred head. <1>

DOE survey of St John's Abbey Gatehouse. Grade I. The only remains of the Abbey of St John the Baptist, a late Benedictine C11 foundation. The gatehouse was built in the later C15, 2 storeys, of rubble and brick faced in knapped flint work set in stone panels with cusped heads. There are 2 flanking octagonal turrets to the front, and the gate hall has a ribbed stone vault roof. The back part of the building was rebuilt in C17 brick after damage during the siege of 1648.<2>

Betteley & Pevsner (2007) state, 'It is a splendid piece of display, characteristically more ornate to the outer world than to the abbey precincts. Flint outer façade with a great deal of flushwork decoration, chiefly shafts and blank crocketed arches. Tall carriageway with four-centred head and tall niches above and to the l. and r. Below the r. niche the entrance for pedestrians, also with four-centred head. Two two-light upper windows and battlements. Flanking polygonal angle turrets with big crocketed pinnacles. No flushwork on the other side and only one wide gateway with a much simpler arch moulding. Inside the gateway is a star-shaped lierne-vault. Extensively restored on the C19 by Major-General Montagu of the Royal Engineers; this included replacing details of the upper storey damaged when the gatehouse was stormed by Parliamentary troops in 1648. E. of the gatehouse are the N. and E. walls of a C15 porter's lodge'.<3>

A summary of historical references in held in the Essex HER under St John's Abbey Gatehouse.<4>

Two digital photographs of St John's Abbey Gatehouse, taken in August 2016.<5>