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City of London, London

Prior approval drawings in the City of London

Prior approval drawings in the City of London are almost always about turning offices and shops into homes, because only 2 per cent of households live in a house and the latest returns show 0 larger home extension prior approvals granted. We are MCIAT chartered architectural technologists, and we test Class MA conversions against the continuous-use and space-standard rules. The council has 56 days to decide.

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We use it to check conservation areas and constraints.
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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 prior approval drawings

    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

    Prior approval drawings in the City of London: Class MA first

    The Square Mile has almost no houses of the kind the larger home extension route needs, so the realistic prior approval here is Class MA, which turns commercial, business or service premises into homes. The key test is continuous use: Class E to C3 needs 2 years' continuous Class E use before the prior approval application.

    The council decides within 56 days, and any home formed this way is covered by this rule: New homes made under PD must meet the nationally described space standard. We test every flat against it before showing you options, because a layout that misses the standard fails the whole application.

    The returns reflect all this: 0 larger home extension and 0 upward extension prior approvals were granted, and 0 refused, in the period.

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

    Local figures for City of London

    Figures with their unit, period and source
    MeasureValuePeriodSource
    Larger home extension prior approvals granted0 decisions2025 Q2 to 2026 Q1 (1 Apr 2025 to 31 Mar 2026)assets.publishing.service.gov.uk
    Upward home extension prior approvals granted0 decisions2025 Q2 to 2026 Q1 (1 Apr 2025 to 31 Mar 2026)assets.publishing.service.gov.uk
    Conservation areas28 named conservation areas published by the council—planning.data.gov.uk
    Listed building entries637 list entries (Historic England, within the LPA boundary)—planning.data.gov.uk
    Registered parks and gardens5 registered parks and gardens intersecting the LPA boundary (Historic England)—planning.data.gov.uk
    Households living in a house2 % of households living in a house or bungalow (detached, semi-detached or terraced)Census 2021nomisweb.co.uk
    Domestic gardens share of land (GLUD 2005)0.1 % of land that is domestic garden (GLUD 2005)2005data.london.gov.uk
    Lawful development certificate applications (PS1)16 certificates2025 Q2 to 2026 Q1 (1 Apr 2025 to 31 Mar 2026)assets.publishing.service.gov.uk
    Sch 2 Pt 3 para W(11)(c)56 days—legislation.gov.uk
    Sch 2 Pt 3 Class MA, para MA.1(1)(b)Class E to C3 needs 2 years' continuous Class E use before the prior approval application—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 City of London
    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

    Designations across the Square Mile

    The council publishes 28 conservation areas in a very small area, so a large share of the City is covered, and Historic England records 637 list entries. Both can shape what change a building will accept, even where Class MA is open.

    The City also holds 5 registered parks and gardens and 5 entries on the Heritage at Risk register. We check each against a site in the free constraints check.

    The local plan was adopted in 2,015, and the council's residential guidance includes the Barbican Estate Listed Building Management Guidelines: Volume I Introduction and Volume II Residential (SPD), which governs alterations in the Barbican.

    Homes, gardens and householder decisions

    Domestic gardens cover just 0.1 per cent of the land, so the rear extension that drives prior approval elsewhere has little to work with. The council decided 1 householder application in the latest twelve months and recorded 16 lawful development certificate applications.

    Because the sample is so small, we do not read patterns into it. Instead we read the building: its history of use, its structure, daylight to the new rooms and the neighbours' outlook.

    Where a flat or a maisonette is involved, leases and freeholder consent matter as much as the council.

    How we prepare a City of London notification

    For a conversion we start with evidence of continuous use, then measure each floor, test layouts against the space standard and check ventilation and natural light. A written description, a site plan and plans of each proposed flat go to the council with the application.

    We also advise on the fire strategy, sound insulation between flats and refuse and cycle storage, because the council may raise them even though the prior approval tests are narrow.

    Someone who did not draw the set checks it. If the building or use fails Class MA, we say so before you pay for drawings and suggest the route that is open.

    Evidence you will need for a conversion

    The strongest Class MA notifications arrive with evidence attached: business rates records, leases, utility bills or tenancy agreements that show the premises used continuously. In the Order's own terms, Class E to C3 needs 2 years' continuous Class E use before the prior approval application.

    We also gather the freeholder's details, the existing floor plans and a survey of daylight and ceiling heights, because the council may ask about them even though they are not formal tests.

    The City adds one more practical issue: a building can share structure, services and escape routes with their neighbours. We map those links early, so the conversion is designed around them and the officer sees that new homes will have safe, independent access, proper ventilation and a workable layout.

    If the building also has a listing or sits in one of the conservation areas, we separate the prior approval from the consents that may still be needed for external changes.

    Other routes in the City

    If Class MA is closed, planning drawings in the City of London prepare a full application, and a Lawful Development Certificate in the City of London can prove an existing use. Our change of use drawings page covers the wider picture.

    The architectural drawings in the City of London page lists the rest, and neighbouring pages include prior approval drawings in Westminster and prior approval drawings in Tower Hamlets.

    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 City of London

    Prior approval drawings nearby

    Questions

    Can I extend a City flat under prior approval?

    No. The larger home extension route is for houses, and only 2 per cent of households here live in one.

    How long does a Class MA decision take?

    The council has 56 days, and we cannot promise a decision date.

    Does a conservation area block Class MA?

    Not by itself, but the City has 28 and we check each building's constraints before quoting.

    What is the council fee?

    For a larger home extension or extra storeys it is £249; other prior approvals have their own fees.

    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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