It is not known if these sections of ditch were once a continuous feature or were built at separate times and had different functions. These sections are most likely to be of Iron Age date. Essex Gryme's Dyke, a Scheduled Ancient Monument, is one of a number of large linear earthwork dykes around the oppidium at Colchester. Most of the dykes were built in the late Iron Age to define and protect the important settlement centre of Camulodunum (Colchester), though some can be dated to the early Roman period which is probably when Gryme’s Dyke was constructed. The official scheduling says: "The monument includes the buried and upstanding remains of the middle part of a late Iron Age or Romano-British linear boundary earthwork (Gryme's Dyke) located some 3.5km WSW of Colchester town centre." "Fragments of pottery and a copied coin of the Emperor Claudius allow the bank to be tentatively dated to the period AD 40-75, perhaps constructed on the eve of the Roman conquest (AD 43), but more probably later and possibly as late as the aftermath of the Boudiccan revolt (AD 60-61)." Greater London Grim's Ditch also called Grim's Dyke stretches from Harrow Weald to Bushey Heath on the north western edge of Greater London. It extends for some 3 km but has been badly damaged by housing development in the twentieth century. The earthwork runs just south of the former county boundary between Hertfordshire and Middlesex. There is another earthwork close by in Pear Wood, Brockley Hill that has been suggested as an eastern continuation of the Grim's Dyke. This monument is of Roman or post-Roman date and runs at ninety degrees to Watling Street. A nearby house built in 1870-72, Grim's Dyke (sometimes also called Graeme's Dyke), was named after the earthworks. The large Victorian Gothic mansion was once the home of the opera librettist W. S. Gilbert and is now operated as a hotel. Excavations in the ground of the Grim's Dyke Hotel in 1979 suggested Grim's Dyke was earlier in date than the Pear Wood monument. Hampshire One Hampshire ditch encloses an area of on the Wiltshire and Dorset borders. The earthwork runs for about , and is a double-banked structure with a ditch between the banks. It crosses the present county boundary into Wiltshire. The Royal Commission's survey of Bokerley Dyke disputed the idea of Grim's Ditch being a single monument, and suggested