Ash Hill Drive, Pinner Green, London Borough of Harrow

Eight trenches were dug within the former Eastern Electricity Pinner Depot. Over most of the site the trenches revealed that the topsoil had been stripped away during the construction of the depot. Although the natural clay had also been disturbed, the survival of subsoil archaeological features was demonstrated by two ditches and a pit. The exact date of these features is uncertain but the character of their fills and a struck flint and daub fragment from the ditches indicate a possible prehistoric date. There was no evidence for Grim's Ditch crossing the site on the line suggested by Horace Stone in 1935. A wide topographic slope was located on the project line of Grim's Ditch. Two features were cut into the natural clay at the bottom of this slope, a ditch and pit, which probably date to the early 17th century. The topographic depression had been filled and levelled off during 17th, 18th and 19th centuries. A sequence of post-medieval deposits was located in the former car park area adjacent to Ash Hill Drive. A considerable quantity of red clay roof tile was recovered, possibly indicating tile production nearby in the 17th century.