The projected course of this dyke runs from Lexden Road / Tapwoods Road northward to link up with Moat Farm Dyke. It is part of Lexden Dyke, a large curving dyke with western ditch enclosing the Late Iron Age settlement at Sheepen. It is undated but generally thought to be one of the earliest parts of the dyke sequence along with Shrub End Dyke and Heath Farm Dyke. Its continuation to the south (MON830) has been tentatively dated to the Sheepen 1 period (AD5-43). A scarp survives through Lexden Springs Open Space but it is not clear how much of the dyke survives.

During the construction of Tapwoods Road the ditch of Lexden Dyke was revealed in the north section of the cut. The ditch was V shaped and 3.81m deep, with an estimated width of about 6m. A 4th century coin was picked out of the section about 0.9m from the base of the ditch. <1>

A sewer trench along Lexden Road was examined, where it crossed the line of the dyke at the junction with Tapwoods Road. There was an accumulation layer of 1.06m but no clear road surfaces. The road has been lowered by several meters, possibly within the last hundred years with the intention of helping coaches in icy weather <2>