Harrow

Local plan

Harrow’s Local Plan 2021–2041 was adopted on 24 March 2026, replacing the 2012 Core Strategy, the 2013 Development Management Policies, Site Allocations and Harrow and Wealdstone Area Action Plan, together with their previous policies map. [1][2]

It forms the borough’s development plan alongside the London Plan and the West London Waste Plan 2015; the earlier documents are not the starting point for a new application. [1][2]

Relevant checks include GR1 for design, layout and neighbours’ amenity, HE1 for heritage, GR10 for infill and backland development, and GR4A and CN3 for basement and flood matters. [3][4]

The adoption statement incorporates the Inspector’s modifications and additional modifications, so use the final policy text and current site mapping rather than an unmodified consultation draft, and resolve the basement-policy issue described below before relying on it. [2][4]

Householder design guide

The council still publishes the Residential Design Guide SPD 2010 for new homes, conversions and extensions, but it must be read alongside the adopted 2026 Local Plan rather than as a replacement for it. [1][5][6]

Chapter 6 covers extensions and alterations, including their scale, siting, relationship to neighbouring windows and effects on the street; the guide’s 45-degree assessment is expressly not a mechanical pass-or-fail test and allows for site circumstances. [6]

For first-floor and two-storey extensions, the guide explains horizontal and vertical daylight checks, so showing compliance on a floor plan alone does not reproduce its assessment. [6]

Its historical policy references and space-standard appendix should not be treated as a current national permissions or building-regulations checklist, and conservation-area properties require their own area guidance as well. [1][6][17][18]

Validation list

Harrow’s current application webpage links to a local validation checklist dated 1 February 2024, which should be used with current national requirements rather than assumed to reflect the new Local Plan automatically. [7][8]

Its householder row requests application and ownership documents, a location plan and block plan, existing and proposed drawings, relevant sections and levels, roof plans, CIL information and the application fee, with additional evidence depending on the proposal. [8]

The checklist still cites superseded local policies, so confirm the applicable assessment requirements against the adopted plan and DM2 of the NPPF published on 17 August 2026, which addresses proportionate application information; this is not advice to disregard the council’s submission list. [2][8][9][10]

For biodiversity net gain, current national guidance retains the householder exemption and, from 6 August 2026, exempts sites of 0.2 hectares or less unless priority habitat is affected, while removing the automatic self-build exemption for applications made on or after that date. [11]

Article 4 directions

A borough-wide Article 4 direction took effect on 12 June 2026, withdrawing the Class L(b) permitted-development route from a C3 dwellinghouse to a C4 small HMO; the sealed schedule does not withdraw the reverse change through this direction. [12][13][14]

Cabinet approved confirmation on 24 September 2026, and its decision record gives 3 October 2026 as the implementation date if not called in, with no call-ins recorded when checked; that is separate from the direction’s original June commencement. [15][16]

Heritage directions must also be checked by property and type of work: Pinnerwood Park’s published guidance distinguishes its core and outer areas rather than applying identical controls to every alteration. [18][19]

The Brookshill Drive and Grimsdyke Estate summary likewise identifies selected properties and different controls, so its conservation-area boundary map is not a substitute for the relevant Article 4 instrument and property schedule. [21][22]

Conservation areas

Harrow’s current heritage webpage lists 30 conservation areas, with area appraisals, management guidance and boundary maps linked through the council’s conservation directories. [17]

Use the documents for the actual property, because the Pinner and Harrow Weald directories contain different area guidance and identify Article 4 controls separately. [18][21]

For example, Pinnerwood Park’s management strategy addresses extension bulk, roof form, windows and front gardens, but does not impose a blanket ban on replacement double glazing: it describes circumstances in which matching timber replacements can be acceptable and requests detailed cross-sections. [20]

For an address-specific check, the published conservation contact is conservation@harrow.gov.uk, telephone 020 8736 6101; establish the current boundary and any separate direction rather than assuming the same controls apply throughout every area. [17][19][22]

Basement policy

GR4A, in the Inspector’s modifications incorporated at adoption, conditionally supports ancillary basements, limits their extent to 50% of the site’s amenity spaces, and restricts projection into the rear garden to 50% of the host dwelling’s depth measured from its principal rear elevation, not half the garden’s depth. [2][4]

It protects neighbours, groundwater, stability and trees, requires internal access and a Construction Method Statement for all basement proposals, and does not support self-contained homes or habitable basement space in Flood Zones 3a/3b. [4]

However, CN3(F) in the same schedule prohibits basement development in Flood Zone 3b and contains wider refusal wording for new dwellings or additional habitable basement accommodation. [4]

The relationship between these provisions needs checking against the final consolidated plan and any additional modifications, with written council clarification before relying on GR4A for a habitable basement; do not assume that meeting the garden and depth criteria makes every habitable-basement proposal acceptable. [2][4]

CIL rates

Harrow’s published 2026 indexed local CIL rate for Class C3 residential development is £196.43/m², under its borough-wide charging schedule effective from 1 October 2013. [23][24]

The GLA’s separate 2026 ordinary Mayoral CIL2 rate for Harrow is £72.73/m²; both figures already include their respective indexation and are not themselves a calculated project bill. [24][25]

Other uses have different local rates, and the local summary retains historical use-class descriptions, so do not apply a single residential or commercial rate indiscriminately: obtain the correct category and chargeable-floor-area calculation, including any available deductions or relief, from HarrowCIL@harrow.gov.uk. [23][24]

The July 2026 consultation on temporary London CIL relief is a proposal, not evidence that a discount can already be claimed, and no proposed reduction has been applied to these published rates. [30]

Pre-application advice

Use Harrow’s pre-application advice service with the site address, location plan, scaled proposal drawings, site photographs and the questions on which advice is needed. [26][27]

The tariff effective 1 April 2026 lists ordinary householder advice at £324.40 for a written response or £530.80 for a meeting and written response, including VAT. [27]

For one new dwelling, the corresponding published prices are £1,469.60 and £1,749.90, including VAT, and specialist input or additional services can attract separate charges. [27]

Confirm the response programme before booking: the live webpage gives a 15-working-day target for householder and small-business written advice, whereas the 2026 notes give 20 working days for written responses, so confirm the expected response date when booking; neither target guarantees delivery. [26][27]

Building control

Harrow Building Control’s published contact is bcontrol@harrow.gov.uk, telephone 020 8736 6058, with postal applications addressed to Building Control, PO Box 37, Harrow, HA3 3QZ. [28]

The council provides online submission through its linked portal and downloadable full-plans, building-notice and regularisation forms; the portal’s free submission service does not mean building-control approval is free. [28]

The current charging scheme took effect on 6 April 2026, and the application page links work-specific charges and a fee-quotation service rather than one price for all projects. [28][29]

For inspections, the council recommends booking by telephone with 24 hours’ notice, requires 48 hours for email requests, and offers same-day telephone bookings made before 9am only subject to surveyor availability, not as an unconditional promise. [28]

The 2026 Future Homes and Buildings Standards regulations generally commence on 24 March 2027. Specified provisions for higher-risk building work and work to existing higher-risk buildings commence on 24 September 2027, with separate transitional arrangements. Confirm the provisions, application and start dates applicable to the project; the new-home standard is not a blanket requirement to retrofit an existing home. [31]