A trial-trenched evaluation was carried out by Colchester Archaeological Trust on the former site of the Garrison Officers Club building which had been destroyed by fire. The site had been cleared of fire damaged buildings of the officers club down to ground floor slab level leaving only the squash courts standing to the rear (north) of the clubhouse.<1> Three evaluation trenches were cut in the first instance, and two more were added when structural remains were discovered. The evaluation consisted initially of three trial-trenches (T1-T3). Trench 1 (8m long) was located north of the extant squash court and was aligned NW-SE (to aid the identification of any E-W orientated graves in this area). T2 (N-S and 25m long) and T3 (E-W and 17m long) were placed within the footprint of the demolished clubhouse to examine the conjectural layout of the abbey church. The discovery of substantial robber trenches (ie the abbey church) led to the opening up of a further two trenches: a series of linked trenches essentially forming one N-S trench 20m long (T4) along the western edge of the clubhouse footprint, and T5 (10m long and N-S) positioned midway between T2 and T4 to intercept the extrapolated position of robbed-out wall lines seen in the northern end of T2. The parts of the Abbey Church of St John's exposed in the evaluation were the west wall, the north and south nave walls, and internal walls which are probably the south wall of the north aisle and the north wall of the south aisle. No superstructure survived. The only below-ground structure was a length of footings for the west church wall. To judge by the evaluated part of the church site, the church has been completely demolished (probably in the 17th century), and all walls and floors removed. Notable finds included painted glass and decorated floor tiles, presumably from the church structure. None of the original church structure survived, but the west end of its ground-plan is defined by the position of robber trenches. Four east/west-aligned walls were defined by robber trenches. From N to S across the site, it is proposed that these were: • the N nave wall (robber trench F20) intercepted by the N end of T2 and T5. • the south wall of a N aisle (robber trench F18) in T2 and the centre of T5 • the north wall of a S aisle (robber trench F4), in T2. • the S nave wall (robber trench F1), in T2 and T3. Further to these, another very large N-S aligned robber trench in T4 (F33 and F39) appears to define the W nave wall, although it remains to be established why it was not quite at right angles to the S nave wall (ie, robber trench F1). Non-church finds included a few Roman pits, two medieval inhumations (40m to the north of the north wall of the church), and many pits and much robbing activity probably connected with the conversion of part of the demolished church into the Lucas House which occupied the (church) site until it was demolished in the late 17th century (after it suffered severe damage in the civil war), or with the military use of the site thereafter. There were a number of features in Trench 2 which predated the church sequence. These contained Roman finds, and it is most likely that they were of Roman date (although it is possible that they were medieval features containing residual Roman material. They were : F2: Small pit cutting natural L4. Sandy silt fill, with oyster shell. Appeared to cut F9. F7: Small part of a pit at the extreme S end of T2. Cut natural L4, contained one piece of Roman pottery, oyster shell and other inclusions. F8: Ditch, E-W aligned, and with V-shaped profile. Contained large quantity of oyster and mussel shells. Based on the similarity of the fills, it was infilled the same time as the gully F9 directly to its south. Cut by robber trench F1. Fifteen Roman sherds. F9: E-W gully alongside and directly S of ditch F8. Roman pottery in fill. F19: Ditch, E-W orientated, cutting natural L4 at N end of T2. Unexcavated, surface finds only, all Roman. Much slag in this feature. Also in the centre of T2, there was a group of much larger features referred to in site note as ‘Pit complex A’ . None of them were excavated, and all finds were recovered from the surface of the features: They were: F10: Large pit, with very pronounced tip line of oyster shells. Only partially in T2. Cut pit F11. Ten Roman sherds.