The unique and important dyke system west of Colchester consisting of a complex system of man made banks and ditches. Several lengths are Scheduled.<1> The dyke system is complex and much research remains to be done. It consists of banks and ditches carefully juxtaposed and making use of natural features such as rivers, streams, marshes, woods and changes in land level.
The general chronological sequence is as follows:
Firstly, the Heath Farm Dyke (11626) broadly enclosing the Gosbecks area, but now virtually destroyed.
The next stage indicates a change in emphasis to the area enclosed by the sharp bend in the River Colne to the north-west of the modern town, which occured about the time of Cunobelin's accession -AD 10. Sheepen Dyke (11641) encloses settlement on the Hillyfields, Lexden Dyke (11628) skirts the Iron Age cemetery and extends across the river to the Moat Farm Dyke (11627), Shrub End Dyke (11640) provides the outer line of this triple defensive system.
During the reign of Cunobelin more dykes were added which, if those on the north side of the river are to be included, would have enclosed a total area of nearly 25 square miles; these were Kidmans Dyke (11630), Olivers Dyke (11631, 11632), Berechurch Dyke (11633), Prettygate Dyke (11639) and Gosbecks Dyke (11634).
Excavations have shown that the dyke system not only continued in use after the Roman conquest but was also added to and modified by Triple Dyke (11636) and Grymes Dyke (11637, 11638), the latter added, possibly in two phases as the new perimeter.<2><3> The first field survey of the dykes was by Lufkin and Smith in 1722, later surveyed by the RCHM in 1922 and there were further surveys in 1932 and a series of aerial photos by O.G.S. Crawford in 1933. In 1932-3 test excavations in Lexden Park produced the first concrete evidence for dating the dyke system as a whole to the pre-Roman Iron Age. The dykes were not all planned to a single purpose and the system grew by stages. In general the earthworks are composed of a rampart and ditch in straight or virtually straight lengths planned to make the earthwork effective without need of further adaptation to the contours, eg, Grymes, Triple, Lexden, Moat Farm, Berechurch and Sheepen dykes. A second group comprises only the works centred on Cheshunt Field - only discernible to the west of this area at the present day - which are curved to follow contours.<4> urgency due to the pressures on this terribly important monument. As the

Site Management: = "The following is suggested as needs for positive management as a matter of system is fairly well established it should be thorroughly checked with a view to increasing the amount scheduled significantly. Ownership must be established. The boundary of the scheduled area must be elucidated along the entire length on the ground as well as on maps to stop the encroachment. All owners and adjacent owners must be notified. All this will be an extremely lengthy exercise but should be carried out as soon as possible. It is beyond the normal work load of an FMW. <1>

Site Assessment = Much of the dykes is now footpath but some parts are in private gardens or fields. There is much evidence of damage, mainly encroachment onto the bank by gardens and landscaping. Actual ownership of the dykes seems in places to be in doubt; there have been no overall management initiatives. <1>