Grim's Ditch: four linear sections between Uxbridge Road and Oxhey Lane


Heritage Category:
Scheduled Monument
List Entry Number:
Date first listed:


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The building or site itself may lie within the boundary of more than one authority.

Greater London Authority
Harrow (London Borough)
National Grid Reference:
TQ 12467 91146, TQ 12558 91399, TQ 12678 91600, TQ 13265 91994


A 1.04km length of Grim’s Ditch running north-east from Uxbridge Road towards Oxhey Lane.

Reasons for Designation

Linear boundaries are substantial earthwork features comprising single or multiple ditches and banks which may extend over distances varying between less than 1km to over 10km. They survive as earthworks or as linear features visible as cropmarks on aerial photographs or as a combination of both. The evidence of excavation and study of associated monuments demonstrate that their construction spans at least a millennium from the Middle Bronze Age, although they may have been re-used later. The scale of many linear boundaries has been taken to indicate that they were constructed by large social groups and were used to mark important boundaries in the landscape; their impressive scale displaying the corporate prestige of their builders. They would have been powerful symbols, often with religious associations, used to define and order the territorial holdings of those groups who constructed them. Linear earthworks are of considerable importance for the analysis of settlement and land use from the Bronze Age onwards; all well preserved examples will normally merit statutory protection.

Despite some disturbance by modern development and landscaping in gardens, the 1.04km length of Grim’s Ditch running north-east from Uxbridge Road towards Oxhey Lane survives relatively well. It will contain archaeological and environmental information relating to the earthwork and the landscape in which it was constructed.


See Details.


This record was the subject of a minor enhancement on 25 March 2015. This record has been generated from an "old county number" (OCN) scheduling record. These are monuments that were not reviewed under the Monuments Protection Programme and are some of our oldest designation records.

The monument includes a 1.04km length of Grim’s Ditch, a prehistoric linear boundary, in four separate areas of protection. It is situated on gently sloping ground at Hatch End, south-west of Harrow Weald Common. This length of Grim’s Ditch, or Grim’s Dyke as it is also known, has been partly landscaped in the gardens of houses but survives as an earthwork and archaeological remains. The earthwork is denoted by a bank, up to 1.5m high, with a ditch to the south, which forms a slight earthwork in places but has otherwise become in-filled and survives as a buried feature. It takes an irregular course running broadly south-west to north-east but has been truncated by later housing development, roads and a railway line, to form four sections. The first section runs for 322m NNE from Uxbridge Road to Grimsdyke Road, largely in the rear gardens of houses on Hallam Gardens. At its northerly end it curves towards the north-east but has been truncated by Grimsdyke Road. It resumes its course for 118m from Shaftesbury Playing Fields towards Colburn Avenue. Beyond Colborn Avenue a 211m section of the earthworks runs north-east in the rear gardens of houses on Sylvia Avenue until the London Overground railway line. The final section of this length runs for 389m from Royston Grove to Oxhey Lane, passing the northern edge of Saddlers Mead where it survives particularly well and is up to 10m wide.

Partial excavation was carried out along part of this length in 1992, followed by a watching brief in 1993, but no finds were recovered.

The Grim’s Ditch of Harrow is a linear earthwork which originally ran from west of Cuckoo Hill to Harrow Weald Common, with a possible easterly continuation in the Pear Wood earthwork. Later developments along the route have truncated or destroyed several parts of it. It consists of a large bank with a ditch on the south side and is thought to have been constructed in two phases. The bank was first built from quarried gravel, sand and clay. The ditch was then dug and some of the spoil deposited to the south. It is thought to be Iron Age in origin, although no conclusive dating evidence has been obtained by excavation. Documentary evidence shows that Grim’s Ditch was certainly in existence by 1306. The original purpose of the earthwork is uncertain but it most likely served to demarcate territorial boundaries.

Grim’s Ditch to the north-east of Oxhey Lane and at Pinner Green are the subject of two separate schedulings.


The contents of this record have been generated from a legacy data system.

Legacy System number:
LO 81
Legacy System:


Greater London SMR 052160/00/00 052160/02/00 052479/00/00. NMR LINEAR 23. PastScape 1043166


This monument is scheduled under the Ancient Monuments and Archaeological Areas Act 1979 as amended as it appears to the Secretary of State to be of national importance. This entry is a copy, the original is held by the Department for Digital, Culture, Media and Sport.

End of official listing

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