A third phase of excavation by K Welsh of OA in advance of continued mineral extraction, revealed a considerable degree of truncation, previously noted across the site (SyAC 99, 232) that became increasingly marked towards the west. As a result, few archaeological features survived in the Phase 3 area other than a sparse scatter of more deeply cut pits, one of which, probably a waterhole, produced a socketed copper-alloy axe of the Sompting type, variant Cardiff II. The type dates from between c 800 and 600 BC and is found throughout much of southern England, the Midlands and South Wales.

Strip, map and sample by K Moon of OAS revealed modern redeposited layers used to create the M25 motorway embankment and confirmed that any archaeological horizons would not be impacted on by the development. Consequently, no finds or features of archaeological interest were revealed.

Excavation by K Welsh of OA. A small hengiform monument, of probable Late Neolithic date, was the earliest feature revealed. Parts of a Late Bronze Age/Early Iron Age field system were also recorded, with evidence for repeated modifications suggesting the relative longevity of the system. The hengiform monument appears to have been incorporated into the field system, rather than being overlain by it, indicating that it was still visible at this time. Evidence for settlement activity contemporary with the field system was also recorded.

Evaluation by N Taylor of OA revealed features associated with the early 20th century development of the site, but no finds or features of archaeological interest.

Two phases of evaluation by OAS on behalf of WSA revealed no finds or features of archaeological interest.

Evaluation and excavation by V Hughes and B Atfield of OA revealed an east–west orientated ditch, from which struck flints of probable Mesolithic or early Neolithic date were recovered, and a north–south orientated ditch. As a result of the evaluation, an area measuring 50 x 30m was investigated. The anticipated ditches proved to date from the Late Iron Age, but a substantial scatter of worked flint, not encountered in the evaluation, was revealed close to the south-east edge of the site.

Strip, map and record excavation by A Simmonds of OA revealed a pit and gully dating from the Early Bronze Age and 94 pits that were attributed to the Middle Bronze Age/Early Iron Age. The remains were dominated by shallow pits, arranged into a northern group of fairly widely scattered, discrete pits and a more densely concentrated group of features cut into a chalk outcrop at the southern end of the site. Some of the pits had clearly defined, deliberately cut edges but others were amorphous and are likely to have been natural in origin, probably representing tree-throw holes.

Evaluation by T Black of OA. Evidence of activity of several periods was found, mostly at the north end of the site. A buried soil covering at least 40m2 was found on the west side of the site that contained a mixture of struck flints of Mesolithic and Bronze Age date. The presence of flints of two dates in the same layer suggests this may have been a colluvial layer containing material derived from further upslope. To the east, a small pit contained undiagnostic struck flints that may be of earlier prehistoric date.

Strip, map and sample by R Brown of OA revealed the truncated remains of 19th century railway structures comprising a turntable, a small building and possible platform edges associated with the Hampton Court branch line. The structures were sited on reworked and mechanically compacted gravels although a full sequence of undisturbed Pleistocene gravels and associated fluvial/alluvial deposits was recorded to the west of the structures.

Evaluation by C Champness of OAS (SU 934 376–931 361). The aim of the exercise was to assess the likely impact on archaeological horizons of a programme of seismic testing proposed in the area. Small charges were detonated at the base of 2m deep auger holes to mimic the proposed seismic test, and the area then excavated to examine the damage caused by the explosives. Two excavations revealed that the blast created a crater c 0.6–0.7m in diameter.