Grim's Ditch or Grim's Dyke or Grimes Dike is a linear earthwork in the

London Borough of Harrow The London Borough of Harrow () is a London boroughs, London borough in northwest London, England; it forms part of Outer London. It borders four other London boroughs London Borough of Barnet, Barnet to the east of ancient Watling Street, Watl ...

, in the historic county of

Middlesex Middlesex (; abbreviation: Middx) is a Historic counties of England, former county in South East England, now mainly within Greater London. Its boundaries largely followed three rivers: the River Thames, Thames in the south, the River Lea, Le ...

. Thought to have been built by the

Catuvellauni The Catuvellauni (Common Brittonic: *''Catu-wellaunī'', "war-chiefs") were a Celtic tribe or state of southeastern Britain before the Roman conquest, attested by inscriptions into the 4th century. The fortunes of the Catuvellauni and thei ...

tribe as a defence against the Romans, it extended east–west about from the edge of

Stanmore Stanmore is part of the London Borough of Harrow in Greater London. It is centred northwest of Charing Cross, lies on the outskirts of the London urban area and includes Stanmore Hill, one of the List of highest points in London, highest point ...

where an elevated neighbourhood of London, Stanmore Hill, adjoins

Bushey Heath Bushey is a town in the Hertsmere borough of Hertfordshire in the East of England. It had a population of 25,328 in the 2011 census, rising to 28,416 in the 2021 census, an increase of 12.19%. This makes Bushey the second most populated town ...

to the far north of

Pinner Green Pinner Green is a small area of Pinner, in the north-west of the London Borough of Harrow, 13.2 miles north-west of Charing Cross. It is a suburban area mostly occupied by family houses and flats, with a small parade of independent shops, a Tesc ...

– Cuckoo Hill. Today the remaining earthworks start mid-way at

Harrow Weald Common Harrow Weald Common is an 18-hectare area of woodland, heath and pasture in Harrow Weald in the London Borough of Harrow. It is considered of considerable importance for wildlife, and it was formerly part of the ''Stanmore and Harrow Weald Common ...

Attributes

Paths

A high path, Old Redding, an old highway, passes through the centre of the ridge and includes a map-marked viewpoint. Other extensive views through breaks in trees are a few hundred yards further up the "high road".

North Basin high point

The immediate

London basin The London Basin is an elongated, roughly triangular sedimentary basin approximately long which underlies London and a large area of south east England, south eastern East Anglia and the adjacent North Sea. The basin formed as a result of compr ...

resembles London's present county: the three most southerly boroughs reach into the

North Downs The North Downs are a ridge of chalk hills in south east England that stretch from Farnham in Surrey to the White Cliffs of Dover in Kent. Much of the North Downs comprises two Area of Outstanding Natural Beauty, Areas of Outstanding Natural Be ...

broad escarpment; those opposing take as their northern edge a broken ridge, low in the north-east, high in the north-west, along which is the Grim's Ditch earthwork. The two highest ridges in Greater London run along its southern edge (bordering

Westerham Westerham is a town and civil parishes in England, civil parish in the Sevenoaks District of Kent, England. It is located 3.4 miles east of Oxted and 6 miles west of Sevenoaks, adjacent to the Kent border with both Greater London and Surrey. I ...

, Kent and

Woodmansterne Woodmansterne is a village in the borough of Reigate and Banstead, Surrey, bordering Greater London, England. It sits on a small plateau of and a southern down slope of the North Downs and its ecclesiastical parish borders continue to span old ...

, Surrey). The next highest point is Stanmore Hill, along the Grim's Ditch, where London adjoins Bushey, Hertfordshire.

Views

*Many parts of Central London can be seen, including the

Shard London Bridge The Shard, also referred to as the Shard London Bridge and formerly London Bridge Tower, is a 72-storey mixed-use development supertall pyramid-shaped skyscraper, designed by the Italian architect Renzo Piano, in Southwark, London, that form ...

, which exceeds the height of all hills in London and the Home Counties. *Beyond

Harrow on the Hill Harrow on the Hill or Harrow-on-the-Hill is a locality and historic village in the borough of London Borough of Harrow, Harrow in Greater London, England. The name refers to Harrow Hill, ,Mills, A., ''Dictionary of London Place Names'', (2001) ...

to the south,

Leith Hill Leith Hill in southern England is the highest summit of the Greensand Ridge, approximately southwest of Dorking, Surrey and southwest of central London. It reaches above sea level, and is the second highest point in southeast England, aft ...

can be seen (and its 20-metre-high tower through binoculars). To the north and west are the Chilterns, and in particular

Coombe Hill, Buckinghamshire Coombe Hill is a hill in The Chilterns, located next to the hamlet of Dunsmore, Buckinghamshire, England, near the small town of Wendover, and overlooking Aylesbury Vale. It is not to be confused with another Coombe Hill on the flank of Had ...

can be seen. The highest point of the earthwork is close to the ''

county top The mountains and hills of the British Isles are categorised into various lists based on different combinations of elevation, prominence, and other criteria such as isolation. These lists are used for peak bagging, whereby hillwalkers attempt ...

'' of the historic county of

, above Grim's Dyke

Golf Golf is a club-and-ball sport in which players use various Golf club, clubs to hit a Golf ball, ball into a series of holes on a golf course, course in as few strokes as possible. Golf, unlike most ball games, cannot and does not use a standa ...

Club on the 'Bushey Heath Walk'

footpath A footpath (also pedestrian way, walking trail, nature trail) is a type of thoroughfare that is intended for use only by pedestrians and not other forms of traffic such as Motor vehicle, motorized vehicles, bicycles and horseback, horses. They ...

. There, a stone marker placed by the Harrow Heritage Trust reads:

This ancient earthwork once stretched through Harrow for six miles from Cuckoo Hill, Pinner to Pear Wood,
Stanmore Stanmore is part of the London Borough of Harrow in Greater London. It is centred northwest of Charing Cross, lies on the outskirts of the London urban area and includes Stanmore Hill, one of the List of highest points in London, highest point ...
, but now only parts remain. Named after Grim (another name for the English King (also the god of death),
Woden Odin (; from ) is a widely revered god in Norse mythology and Germanic paganism. Most surviving information on Odin comes from Norse mythology, but he figures prominently in the recorded history of Northern Europe. This includes the Roman Emp ...
).

Hotel and film location

In the woods stands

Grim's Dyke Grim's Dyke (sometimes called Graeme's Dyke until late 1891)How, Harry ''The Strand Magazine'', Vol. 2, October 1891, pp. 330–41, reprinted at ''The Gilbert and Sullivan Archive'', 20 November 2011 is a house and estate in Harrow Weald, in n ...

, a house designed in 1870 by

Norman Shaw Richard Norman Shaw RA (7 May 1831 – 17 November 1912), also known as Norman Shaw, was a British architect who worked from the 1870s to the 1900s, known for his country houses and for commercial buildings. He is considered to be among the g ...

for the Victorian painter

Frederick Goodall Frederick Goodall (17 September 1822 – 29 July 1904) was a British artist. Life Frederick Goodall was born in London in 1822, the second son of steel line engraver Edward Goodall (1795–1870). He received his education at the Well ...

. Later, it was the country home of

W. S. Gilbert Sir William Schwenck Gilbert (18 November 1836 – 29 May 1911) was an English dramatist, librettist, poet and illustrator best known for his collaboration with composer Arthur Sullivan, which produced fourteen comic operas. The most fam ...

(of

Savoy opera Savoy opera was a style of comic opera that developed in Victorian England in the late 19th century, with W. S. Gilbert and Arthur Sullivan as the original and most successful practitioners. The name is derived from the Savoy Theatre, which imp ...

fame) – he suffered a heart attack and drowned while trying to save a swimmer in the lake in the grounds. It is now a hotel and is often used as a film setting. The house and gatehouse are

listed building In the United Kingdom, a listed building is a structure of particular architectural or historic interest deserving of special protection. Such buildings are placed on one of the four statutory lists maintained by Historic England in England, Hi ...

History

Grim's Dyke may have been built by the

tribe as a defence against the Romans. or as a boundary marker. An excavation in 1979 in the grounds of the Grim's Dyke Hotel gave a radiocarbon date of 50 AD ± 80 years, for a heath in the bank which suggests an Iron Age or Roman date. 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 Watling Street is a historic route in England, running from Dover and London in the southeast, via St Albans to Wroxeter. The road crosses the River Thames at London and was used in Classical Antiquity, Late Antiquity, and throughout the M ...

Trivia

The earthwork gave its name to the

telephone exchange A telephone exchange, telephone switch, or central office is a central component of a telecommunications system in the public switched telephone network (PSTN) or in large enterprises. It facilitates the establishment of communication circuits ...

for Stanmore. The legacy is the first three numbers of many local landlines.

References

;Notes ;References {{reflist Archaeological sites in London Archaeological sites in Hertfordshire Parks and open spaces in the London Borough of Harrow Hills of Hertfordshire Ancient dikes History of the London Borough of Harrow Linear earthworks