Four boundaries read as one
Four of the six conservation areas in Harrow's Stanmore and Edgware group are joined here into one study area of about 49 hectares: Little Common, the largest at about 32.8 hectares, then Stanmore Hill at 7.5, Old Church Lane at 5.7 and Kerry Avenue at 3.0. Each keeps its own boundary, while a single supplementary planning document sets the framework for managing all of them.
Some records that matter here sit with the council rather than in the national datasets, the Article 4 map for the hill above all, and they are cited where they fill a gap. Housing figures come from three statistical areas that overlap the four boundaries without following them, and the borough as a whole is the subject of the Harrow guide.
What council and national records show
Every statement below links to the public record it comes from; sources were re-checked on .
The four designations and the SPD
The four records on planning.data.gov.uk are Little Common, reference 174_HRW_CA22, Stanmore Hill, 174_HRW_CA23, Old Church Lane, 174_HRW_CA24, and Kerry Avenue, 174_HRW_CA25.
None of the four carries a designation date in that national dataset, but Harrow's Article 4 map for the hill states that its conservation area was designated in 1975 and extended in 1980, 1991 and 2002.
Harrow adopted the conservation areas supplementary planning document in December 2013 as a framework for the positive management of the group, to be read with the appraisal and management strategies that form its appendices.
Its special-interest section covers six conservation areas in all, four of which make up this study area.
According to the Article 4 map, the appraisal and management strategy for the hill was adopted at Cabinet on 12 December 2013 as appendix 2 to that SPD.
Article 4 controls on the hill
The national Article 4 dataset on planning.data.gov.uk holds no direction polygon for these four areas, yet Harrow's own Article 4 map sets out classes of permitted development that are controlled where a property fronts a highway, waterway or open space.
Its schedule names cottages and houses on Green Lane and numbered properties on the hill, and the classes listed include Part 1 Class A, the enlargement, improvement or other alteration of a dwellinghouse.
The same map also lists Part 2 Class A, the erection, construction, maintenance, improvement or alteration of a gate, fence, wall or other means of enclosure.
Because a national dataset can lack a direction the council holds, an owner on the hill should check the council's map before treating an extension, a window change or a new front wall as permitted development.
List entries and a locally listed park
Across the four boundaries the NHLE dataset returns 52 list entries, 48 at Grade II and 4 at Grade II*.
The Grade II* entries are Old Stanmore Church, the Church of St John, Stanmore Hall and 73 Stanmore Hill.
A list entry is one record on the national list and may describe a single house, a range of buildings or a boundary wall, so the entry text decides whether listed building consent comes into a project.
Harrow's map also records that Stanmore Recreation Ground, adopted as a locally listed park and garden at Cabinet on 23 September 2021, lies partly within the hill's conservation area.
Gravel over clay, silt and sand
At all five sample points, BGS geology at 1:50,000 places sand and gravel of the Stanmore Gravel Formation over bedrock of the Claygate Member, which it describes as clay, silt and sand.
Sand and gravel drain freely, but a leaking drain or water pipe can carry their fine particles away, so where the BGS superficial layer shows gravel, drainage condition and signs of local settlement get close attention.
The clay within the Claygate Member can still shrink and swell as its moisture changes where footings or roots get down to it, which is why the bedrock layer is read together with the gravel above it.
Gravel thickness and the depth to clay at a given plot are beyond what the regional map can show.
Flood zones
Under 0.1% of the four areas together lies in Flood Zone 2, and the same holds for Flood Zone 3, according to the Environment Agency Flood Map for Planning.
Planning zones omit defences and are not property-level, and surface water, which needs no river at all, is mapped on the long-term flood risk service, so that is checked for an address too.
Housing in three statistical areas
Three LSOAs that overlap the conservation areas most, E01002114, E01002225 and E01002226, hold about 3,240 dwellings in the VOA stock of properties release for 2025, a release that rounds each count to the nearest 10.
Flats and maisonettes are 61.4% of the total in the VOA type breakdown, against 19.1% detached houses, 8.3% terraced houses, 6.8% semi-detached houses and 4.3% bungalows.
Most of the stock postdates 1945 on the VOA build-period table: 33.6% from 1945-1972, 27.5% from 2000 onwards and 21.9% from 1973-1999, together 83.0%, with 10.5% from 1919-1939, 2.2% from 1900-1918, 4.3% before 1900 and 0.3% undated.
Bands F to H hold 42.0% of dwellings in the VOA band counts, split 11.7% in F, 20.4% in G and 9.9% in H.
The LSOAs approximate the conservation areas without matching them, and the VOA figures cannot tell a listed cottage from a modern flat in the same statistical area, so a building's age and construction are confirmed on site.
Area guides and practice services
Each guide in the first list is written for one kind of instruction in this part of Harrow, and the second list links the matching service page for the whole practice.
Guides for nearby areas
Borough-wide coverage is in the Harrow guide, while Pinner, Harrow on the Hill and Mill Hill have neighbouring guides, each drawn on a study area of its own.
Common questions on the four areas
Which conservation areas does this page combine?
Little Common, Stanmore Hill, Old Church Lane and Kerry Avenue, about 49 hectares together on planning.data.gov.uk. All four belong to a group of six that Harrow manages through a supplementary planning document adopted in December 2013, read with the appraisals that form its appendices.
Is there an Article 4 direction on the hill?
Yes. Harrow's Article 4 map lists properties on Green Lane and on the hill where classes of permitted development are controlled where they front a highway, waterway or open space, including alterations to a dwellinghouse and gates, fences and walls. The national dataset shows none, so the council's map is the one to check.
How many list entries sit inside the four boundaries?
The NHLE dataset returns 52: 48 at Grade II and 4 at Grade II*, two of them churches. One entry can cover several structures, so the figure counts records rather than buildings, and each address is looked up on its own.
Why does gravel ground matter for a house here?
Sand and gravel appear at all five sample points on the BGS map, over Claygate Member beds. Gravel drains well but can be washed out by a leaking drain, while the clay below can move with moisture, so drains and cracks are both checked during an inspection.
Are homes in the area mostly old?
Not on the VOA figures. In the three LSOAs used, the VOA's 2025 property stock tables date 83.0% of dwellings to 1945 or later and 4.3% to before 1900, and 61.4% are flats or maisonettes. Those LSOAs extend beyond the conservation areas, so a building's own age is still confirmed.
What is the status of the recreation ground?
Harrow's Article 4 map records it as a locally listed park and garden, adopted at Cabinet on 23 September 2021 and lying partly within the hill's conservation area. Local listing is a council designation, so its bearing on a nearby scheme is a matter for Harrow's planning team.
How we work on an instruction
Hampstead Chartered Surveyors is a RICS-regulated firm (RICS Regulated Firm No. 923064) working from its registered Hampstead NW3 office. The firm does not claim premises, staff or completed instructions in an individual locality, and it does not treat a neighbourhood name as evidence about a particular building.
An instruction starts with the full address, the decision the client faces and the documents already available, such as leases, drawings, notices or earlier reports. The scope, fee and inspection date are confirmed in writing only after that review, and access to roofs, lofts, basements or common parts is agreed before the visit.
Reports include RICS Level 2 and Level 3 home surveys, building and defect investigations, party wall appointments, reinstatement cost assessments, contract administration and schedules of condition. Each report records what was inspected, what could not be seen and what further investigation the evidence supports.
Public datasets such as the conservation-area register, the National Heritage List for England, British Geological Survey mapping, the Environment Agency flood map and Valuation Office Agency housing statistics describe areas rather than individual properties. They frame questions before an inspection; they never replace it.
Reviewed by Savas Bulduk BSc (Hons) MRICS, Director & Chartered Building Surveyor at Hampstead Chartered Surveyors & Building Consultancy. Last reviewed: . Our people · RICS firm record