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Bromley, London

Biodiversity net gain plans in Bromley

Biodiversity net gain matters a great deal in Bromley, because 51 per cent of it is Green Belt and much of the rest is leafy suburb. Householder work is exempt. A new home, a barn conversion or a scheme on open land is not, and Bromley's validation guidance asks for a statement showing at least the national gain. We quote a fixed price after a free constraints check.

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    Architectural model of a four-storey London stucco townhouse in its terrace, with a portico, area railings, sash windows, a cornice and chimney stacks
    The house as it stands: four storeys over a lower ground floor.Existing Proposed worksAn illustrative model, built for this page.

    How we work on biodiversity net gain plans

    Seven steps from first call to approval.

    The same model cut through the middle: every floor, the stair, the chimney breasts, the new mansard, rear extension and basement in section
    Section through the model: every floor on one datum.

    1. Enquiry and constraints check

      We check the property against conservation areas, listed status, Article 4 directions, tree preservation orders, flood zone and planning history. We choose the right route and send a fixed quote.

    2. Measured survey

      We survey the house on one datum: rooms, levels, boundaries, drains, trees and the neighbours' windows that the 45° and 25° tests depend on.

    3. Design options

      We model the house in Revit and show you options in 3D and plan, with the planning strategy and the precedents in your street.

    4. Design frozen

      You choose an option in writing. Nothing changes after this without your say.

    5. Independent check

      A second chartered technologist checks every sheet against the council's validation checklist and the policy. A senior review signs it off before anything is submitted.

    6. Submission

      We prepare the forms, certificates, fee and documents and submit through the Planning Portal.

    7. Officer liaison

      We answer the planning officer and make any amendments within five working days, at no charge until approval.

    Free redraws until approval. Every drawing set is checked independently, and the checker is never the person who drew it.

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    Brick cottage with a tiled roof, chimneys and a front dormer window

    What Bromley's validation guidance requires

    Bromley's validation guidance and list of local information requirements, last agreed in December, says a net gain statement or plan is required for all major and non-major applications unless they are exempt. It must show the minimum gain, and the council's recorded value is 10% (statutory). It states no uplift beyond that.

    One detail helps smaller schemes. For non-major development the guidance allows the small sites metric, a simplified spreadsheet that is quicker to complete. It cannot be used where priority habitat, a protected site or a protected species is present, and in Bromley that exclusion is a real possibility, because of the amount of open land.

    The guidance is also candid about timing. The statement belongs in the submission, not in a later condition response, so an applicant who leaves it until after validation risks the application being returned. We therefore treat the survey as the first task on any Bromley scheme that is not obviously exempt, and book the ecologist before the drawings are finished.

    Rear view of brick terraced houses in London with slate roofs and chimney stacks along the shared roofline

    Local figures for Bromley

    Figures with their unit, period and source
    MeasureValuePeriodSource
    Green Belt share of the council area51 % of council area covered by green-belt polygons—planning.data.gov.uk
    BNG Statement/Plan required for all major and non-major applications unless exempt, demonstrating a minimum 10% net gain; non-major applications may use the Small Sites Metric. No uplift above 10% stated.10% (statutory)—bromley.gov.uk, Bromley Validation Guidance and List of Requirements - Planning Applications (agreed 12 December 2024), pp.16, 24, 'Biodiversity Net Gain'
    Domestic gardens share of land (GLUD 2005)23.4 % of land that is domestic garden (GLUD 2005)2005data.london.gov.uk
    Conservation areas47 named conservation areas published by the council—planning.data.gov.uk
    Listed building entries412 list entries (Historic England, within the LPA boundary)—planning.data.gov.uk
    Householder applications granted78.6 %1 July 2025 - 30 June 2026assets.publishing.service.gov.uk
    Householder appeals allowed37.6 % of householder appeals alloweddecision dates 1 Jul 2021 to 30 Jun 2026assets.publishing.service.gov.uk
    Environment Act 2021 Sch 14 para 2, inserting Sch 7A TCPA 1990: 'relevant percentage' 10%10 %—legislation.gov.uk
    'Developments of 0.2 hectares or below': from 6 August 2026 BNG does not apply where the site area within the red line boundary is 0.2 ha or below0.2 ha—gov.uk
    'Developments subject to the de minimis rule': impact on less than 25 m2 (5 m by 5 m) of on-site habitat25 m2—gov.uk

    A blank value means the figure has not been published, not that there are none. Check your own address with the council.

    Councils bordering Bromley
    Which application your project needsLawful Development Certificate decision: 8 weeks. Prior approval decision: 42 days. Householder decision: 8 weeksYour projectWithin permitted development?Lawful Development CertificatePrior approvalHouseholder applicationYesLarger rear extensionNoABC

    Which application your project needs

    The usual route for a house; flats and listed buildings follow other rules.

    A · Lawful Development Certificate decision
    8 weeks
    B · Prior approval decision
    42 days
    C · Householder decision
    8 weeks

    A Green Belt majority changes the survey

    With 51 per cent of the borough covered by Green Belt polygons, many Bromley plots sit beside or inside land that is meadow, woodland or parkland. A site next to such land is more likely to contain, or sit near, priority habitat, and the metric treats those habitats at a far higher value than a suburban lawn.

    That is why we start with a desk study of the surrounding land before we send an ecologist. If the site is clean, the small site route may open and the plan is short. If it is not, a full survey is the honest answer, and it is better to know that before you commit to a design.

    A hedge, a pond, an old orchard or a patch of rough grass at the bottom of a garden can all matter. Keep the plot as it is, and keep dated photographs.

    Where a scheme does touch land of higher value, there is usually a design answer. A house can often be moved or reduced so that a woodland edge or an orchard is left whole, which keeps the baseline low in the lost-habitat column and avoids the need to buy units elsewhere. Your drawings should show that choice, and we say why on the sheet.

    Gardens, conservation areas and listed buildings

    Domestic gardens make up 23.4 per cent of the borough's land, and 68.6 per cent of households live in a house. Bromley also has 47 conservation areas and 412 listed building entries, which limit how a plot can be changed and so decide how much habitat is left after development.

    The council's Urban Design Guide SPD sits alongside a Local Plan adopted in 2,019. We read both with the metric, so the landscape and built form on the drawings agree with the figures in the spreadsheet.

    If your project is a new home, our new build drawings include the landscape sheet the plan relies on.

    Which Bromley projects are exempt

    Householder applications and permitted development are exempt, which covers most extensions and loft conversions. Sites of 0.2 hectares or below are exempt, and the de minimis rule excludes impacts below 25 square metres of habitat.

    Even where an exemption applies, the form must say so. In Bromley the council granted 78.6 per cent of householder applications in the latest returns, and it decided 89.1 per cent of them in time, so an invalid form is an avoidable delay.

    When a refusal is appealed, the record is worth knowing: the Planning Inspectorate allowed 37.6 per cent of the 502 householder appeals it decided in the borough.

    Price and next step

    A plan has no list price, because the cost follows the habitats and the survey needed. You receive a fixed quote after a free constraints check.

    Our biodiversity net gain page covers the national rules, and the Bromley area page lists everything else we offer there. If the case for permission is the bigger question, our planning consultant service can lead it.

    What you receive

    Planning drawing sheet for a rear extension with plans, elevations and sections
    Sample drawing. Planning drawings for a rear extension: plans, elevations and sections on one sheet set.
    Pencil resting on a dimensioned technical drawing beside a scale rule
    The street around you
    Move across the plinth — the blocks rise around the pointer.

    Other services in Bromley

    Biodiversity net gain plans nearby

    Questions

    Can I use the small sites metric in Bromley?

    Often yes for non-major schemes, but not where priority habitat, a protected site or a protected species is present.

    Is Bromley's gain higher than the national figure?

    No. The validation guidance records 10% (statutory) and states no uplift.

    Why does Green Belt matter?

    Green Belt land often borders priority habitat, which the metric values highly and which rules out the small sites metric.

    How long is the gain kept?

    At least 30 years after completion.

    Sources and dates

    City of London skyline glowing at dusk across the Thames under a dramatic orange sky

    Tell us about your property.

    We check the constraints, then send a fixed fee. Messages before 3pm get a reply the same working day.

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