Betsom's Hill is a hill on the North Downs, and the highest point in the county of Kent at 251 metres (823 ft). Situated between Westerham and Tatsfield, at the western edge of the county, it lies close to where the A233 crosses the Downs en route to Biggin Hill. This is the highest part of the North Downs, with Botley Hill the highest point, nearby to the west. The hill lies at the western end of the Kent Downs, an area of outstanding natural beauty.

Geography

The crest of the hill was the location of a Victorian defence fort, one of twelve locations along the North Downs built to protect London in case of attack by foreign invaders crossing the channel. Known as Betsom’s Hill Fort or Westerham Fort, it was part of the London Defence scheme, and was intended to act both as a mobilisation centre for volunteer troops, and as an ammunition store. The fort which consisted of ramparts, casemates and a magazine has been partially demolished and converted for use as workshops, with private houses appropriately named Fort Cottages now occupying the site.

Coordinates: 51°16′17″N 0°04′12″E / 51.27134°N 0.07005°E / 51.27134; 0.07005

Westerham is a town and civil parish in the Sevenoaks District of Kent. It is located on the border of Kent with Greater London and Surrey, bordering Bromley and the Tandridge District. It is located west of Sevenoaks.

It is recorded as early as the 9th century, and was mentioned in the Domesday Book in a Norman form, Oistreham (compare Ouistreham in Normandy, Oistreham in 1086).Hām is Old English for a village or homestead, and so Westerham means a westerly homestead. The River Darent flows through the town, and formerly powered three watermills.

(The spelling Oistreham is probably the result of a confusion with Ouistreham in Normandy facing England. The etymology of the name Oistreham > Ouistreham is probably a confusion between "west" and "east". Old Saxon *Westarham or Old English *Westreham should have given *Westreham > *Vestreham or *Estreham in medieval Norman, see Étréham. Oistreham (Normandy) is much better explained by Old Saxon ōstar = "east", with similar phonetic evolution as Latin ostrea = "oyster", Old French oistre > English "oyster". We cannot exclude an artificial influence of this word that would have corrupted the initial Westre- to Oistre-, but it is impossible to prove. That is the reason why the Old Saxon ōstar is a better solution for Ouistreham.)