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Islington, London

Retrospective planning application in Islington

In Islington a retrospective planning application usually concerns a flat, a Georgian or Victorian terrace, or a basement dug without consent. The council granted 92.6 per cent of its 337 householder decisions in its latest year. Fixed quote after a free constraints check.

Fixed quote after a free constraints check

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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 retrospective planning applications

    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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    Pencil resting on a dimensioned technical drawing beside a scale rule

    Islington policy for built work in terraces and flats

    The council applies the Islington Local Plan: Strategic and Development Management Policies, Site Allocations, and Bunhill and Clerkenwell Area Action Plan, adopted in 2,023, with the Islington Urban Design Guide SPD guiding the detail of extensions and roof additions. For built work the question is whether the finished result respects the rhythm of the terrace, so we draw the whole terrace elevation and not just your own front.

    Only 16.3 per cent of Islington households live in a house, so the usual subject is a rear addition to a maisonette or a roof terrace on a mansard. Where a lease is involved, the freeholder may also need to approve the change, and we mention that early.

    Rear closet wings, glazed side infills and new dormers are the details officers look at first. Each gets a dimensioned section in our drawings.

    Rows of brick terraced houses and gardens on a residential street

    Local figures for Islington

    Figures with their unit, period and source
    MeasureValuePeriodSource
    Conservation areas41 named conservation areas published by the council—planning.data.gov.uk
    Listed building entries1,050 list entries (Historic England, within the LPA boundary)—planning.data.gov.uk
    Grade II listed entries1,002 list entries—planning.data.gov.uk
    Heritage at Risk entries33 Heritage at Risk Register entries within the LPA boundary (Historic England)—planning.data.gov.uk
    Households living in a house16.3 % of households living in a house or bungalow (detached, semi-detached or terraced)Census 2021nomisweb.co.uk
    Householder decisions337 decisions1 July 2025 - 30 June 2026assets.publishing.service.gov.uk
    Householder applications granted92.6 %1 July 2025 - 30 June 2026assets.publishing.service.gov.uk
    Householder applications decided in time98.8 % decided within 8 weeks or an agreed extended period1 July 2025 - 30 June 2026assets.publishing.service.gov.uk
    Minor applications granted86.5 %1 July 2025 - 30 June 2026assets.publishing.service.gov.uk
    Lawful development certificate applications (PS1)141 certificates2025 Q2 to 2026 Q1 (1 Apr 2025 to 31 Mar 2026)assets.publishing.service.gov.uk
    Householder: alterations/extensions to a single dwellinghouse, from 1 Apr 2026548 GBP—ribblevalley.gov.uk
    TCPA 1990 s171B(1)-(3) as substituted by LURA 2023 s115, in force 25 Apr 202410 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 Islington
    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

    Basements built without permission

    A basement is the most serious kind of retrospective case, and Islington has a dedicated Basement Development SPD. It expects structural and hydrological evidence that is difficult to produce after the digging is finished, and an officer will look for it.

    Engineering calculations come from a structural engineer, which we can arrange, and we record the as-built excavation on the drawings. Where the basement is large we also commission a basement impact assessment in Islington so the council has the technical case in one submission.

    Ordinary cases are simpler. If your work is above ground, the drawing effort is lower and so is the fixed price.

    Heritage that shapes the decision

    Islington has 1,050 list entries, among them 1,002 at Grade II, and 41 conservation areas. Barnsbury, Canonbury and Clerkenwell are the best-known examples, and almost any terrace there will be touched by one designation or another.

    Historic England also lists 33 entries in the borough on its Heritage at Risk Register. If your house is listed, listed building consent is a separate legal matter, and we flag it so you can take advice before submitting.

    Decision rates, time and cost

    The council decided 337 householder cases, and 98.8 per cent met the deadline of 8 weeks or an agreed extension. It granted 92.6 per cent, and 86.5 per cent of minor applications.

    Householder fees are £548, the decision period is 8 weeks, and the enforcement window for most building works is 10 years. Islington charges levy at £300/m² (Zone A); £250/m² (Zone B) — residential dwellings, Use Classes C3 and C4, with mayoral charging at £80 per square metre as the base rate in band 1.

    Owners made 141 lawful development certificate applications in the period, and flats do not have the same permitted development rights as houses.

    Roof terraces, mansards and closet wings

    The commonest above-ground cases in Islington are small in footprint and large in effect: a roof terrace behind a parapet, a mansard that rose a storey higher than the neighbour's, or a glazed infill that closed the gap beside a closet wing. Overlooking, outlook and the terrace skyline are what the officer tests.

    For each, our drawings show a sight-line section from the neighbouring window and a terrace-wide elevation. Those two sheets answer the objections most often raised, and they are cheap to produce while the building is still easy to measure.

    If you are a leaseholder, ask the managing agent for the lease plan and any licence for alterations before we start. A licence can sometimes be given after the event, but the freeholder needs the same drawings the council sees, so we produce one set that serves both.

    What we prepare and where to go next

    The package contains a measured survey, as-built and proposed drawings, a terrace elevation, sections, location and block plans, and a short design note. Our planning drawings in Islington follow the same format and are independently checked.

    The price is fixed after the free check. More information is in architectural drawings in Islington and the retrospective planning page. We also work in Hackney and Camden.

    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.
    Georgian brick terrace with sash windows, arched fanlight doorways, stone steps and iron railings in London
    The street around you
    Move across the plinth — the blocks rise around the pointer.

    Other services in Islington

    Retrospective planning applications nearby

    Questions

    Do flats in Islington have permitted development rights?

    No. Flats and maisonettes do not have the householder rights that houses have, which is why so many cases need full applications. Only 16.3 per cent of households live in a house.

    Can a basement dug without consent be regularised?

    Sometimes. The Basement Development SPD sets the technical evidence the council expects, and we help assemble it.

    How long does the council take?

    A non-major case has 8 weeks, and 98.8 per cent of householder cases met the deadline or an agreed extension.

    Does the council fee change for retrospective work?

    No. The householder fee is £548, the same as for an ordinary application.

    Sources and dates

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    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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