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Merton, London

Biodiversity net gain plans in Merton

Merton is firm that an exemption does not mean silence: its validation checklist asks for a biodiversity statement even where the mandatory gain does not apply. A full plan is needed only for non-exempt schemes, and then the site must finish 10 per cent better than it began. We write both on a fixed quote after a free constraints check.

Fixed quote 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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    Rows of brick terraced houses and gardens on a residential street

    Merton wants a statement even when you are exempt

    The council records this as Exempt schemes still need a statement. Its checklist includes the statutory requirements and a biodiversity statement, and the Local Plan policy on biodiversity supplies the reason.

    For a householder the statement can be short: what is on the site, what the works touch, and why the gain condition does not apply. It still has to exist, and it has to agree with the plans, so that a lawn shown on a drawing is not described as hardstanding in the text.

    We write the statement from the survey drawings and keep it to a page where the facts allow, so that nothing in it can contradict the elevations.

    The statement is also where we record that no priority habitat was found. A single line saying that the site was checked against the national habitat inventory, and what the check showed, answers the question an officer is most likely to ask.

    Think of the statement as a receipt: it proves the question was asked and answered on the record, which is all the validation team is looking for on an exempt scheme.

    Georgian brick terrace with sash windows, arched fanlight doorways, stone steps and iron railings in London

    Local figures for Merton

    Figures with their unit, period and source
    MeasureValuePeriodSource
    Checklist includes statutory BNG requirements and a biodiversity statement even where exempt (Local Plan 2024 Policy O15.3).Exempt schemes still need a statement—merton.gov.uk, Merton Council's Validation Checklist 2024 (December 2024), p.2, p.11
    Domestic gardens share of land (GLUD 2005)27.2 % of land that is domestic garden (GLUD 2005)2005data.london.gov.uk
    Households living in a house60.4 % of households living in a house or bungalow (detached, semi-detached or terraced)Census 2021nomisweb.co.uk
    Registered parks and gardens4 registered parks and gardens intersecting the LPA boundary (Historic England)—planning.data.gov.uk
    Conservation areas28 named conservation areas published by the council—planning.data.gov.uk
    Householder applications granted92.9 %1 July 2025 - 30 June 2026assets.publishing.service.gov.uk
    Minor applications granted82.5 %1 July 2025 - 30 June 2026assets.publishing.service.gov.uk
    Minor application decisions206 decisions1 July 2025 - 30 June 2026assets.publishing.service.gov.uk
    Minor applications decided in time82 % decided within 8 weeks or an agreed extended period1 July 2025 - 30 June 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
    Sch 7A para 9(3) as inserted: enhancement maintained for at least 30 years after completion30 years—legislation.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 Merton
    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

    What sits on a Merton plot

    Domestic gardens cover 27.2 per cent of the borough, and 60.4 per cent of households live in a house. That is the profile of a suburban borough: long rear gardens, mature boundary planting and links to open habitat.

    The borough has 4 registered parks and gardens and 28 conservation areas.

    Most of the work here is extensions and lofts, which are exempt. The plan comes in with a new house in a long garden, a conversion of a detached garage, or a block of flats on a former depot.

    Long gardens are the feature that draws developers to Merton and also the feature that creates the baseline. A garden of mown lawn scores low; one with a mature hedgerow, a pond or rough grassland scores far higher, and the difference decides how much new habitat a replacement house must provide.

    Exemptions and thresholds

    Householder applications and permitted development are exempt. A site of 0.2 hectares or less is exempt unless priority habitat is affected, and impacts under 25 square metres of habitat are de minimis.

    Even so, we write the statement in a form an officer can tick off, covering the baseline, the effect of the works and the exemption relied on. A statement that names the exemption precisely is quick to accept; a vague one invites a query.

    Where a plan is required, the gain is maintained for at least 30 years, and our maintenance notes say who does what in each of those years.

    If you are unsure which category your plot is in, send us a photograph and the plot outline. We can usually tell from those whether the exemption is safe, and we will confirm the answer in writing for your file.

    Decisions in Merton and what it means for timing

    Householder applications are granted 92.9 per cent of the time, and minor applications 82.5 per cent across 206 decisions, of which 82 per cent are decided in time. A file that validates first time protects that record.

    We prepare the statement with the drawings. See our planning drawings service for the full set, and lawful development certificate work where the project may not need permission at all.

    Where an application is refused for another reason and goes to appeal, the biodiversity statement travels with it. Our planning appeals team reuses it without rewriting, so the ecology evidence stays consistent from first submission to the Inspector.

    Price and next step

    There is no list price for a plan, as the work depends on the habitat parcels. A short exemption statement is included in our drawings work. Otherwise you receive a fixed quote after a free constraints check.

    Send the address and a note of what you plan to build. We will tell you what Merton will expect to see.

    If the answer turns out to be that nothing beyond a statement is needed, we say so plainly and do not invent work. The free check exists to separate the schemes that need a metric from those that need one tidy page.

    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.
    Brick cottage with a tiled roof, chimneys and a front dormer window
    The street around you
    Move across the plinth — the blocks rise around the pointer.

    Other services in Merton

    Biodiversity net gain plans nearby

    Questions

    Do exempt schemes in Merton still need a statement?

    Yes. The validation checklist asks for a biodiversity statement even where the mandatory gain does not apply.

    What should the statement say?

    What is on the site, what the works affect and which exemption applies, consistent with the drawings.

    When is a full plan needed?

    For non-exempt schemes such as a new dwelling, which must deliver at least 10 per cent gain.

    Is a small site exempt?

    A site of 0.2 hectares or less is exempt unless priority habitat is affected.

    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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