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Free 2026 London Planning ReportPlanning Permission in Marylebone W1U

Marylebone W1U mansion flats and Harley Street terraces in Westminster City Council's Harley Street conservation area
Marylebone · W1U · Westminster

Planning Permission in Marylebone W1U

Fixed-fee, MCIAT-chartered planning permission for Marylebone (W1U) homeowners — Westminster City Council validation and local constraints handled from the start.

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Marylebone (W1U) sits on the Portman and Howard de Walden estates, and the work is characteristically internal reconfiguration, mansion-flat alterations and change of use — nowhere more so than the Harley Street medical district, where consulting-room, office and residential uses are finely balanced. The terraced grain is consistent and closely protected, so schemes turn on sensitive interiors and correct use classification rather than external enlargement.

With the Harley Street, Portman Estate and East Marylebone conservation areas overlapping much of the district and many buildings listed, most projects involve conservation-area or listed-building consent, and the estate freeholders impose their own consent regime. We confirm the estate, listing grade and conservation boundary before drawing and prepare the application to Westminster City Council's validation standard.

Marylebone W1U mansion flats and Harley Street terraces in Westminster City Council's Harley Street conservation area
Isometric illustration of a Marylebone W1U home planning permission design
Proposed floor plan
Marylebone W1U

Planning in Marylebone (W1U): what to know before you apply

There is no published householder Article 4 direction driving decisions in W1U; the real controls are the overlapping conservation areas, widespread listing, the Harley Street change-of-use context and the Portman and Howard de Walden estates' freeholder consent requirements, all of which we address alongside the council submission.

Typical Marylebone housing stock

Brick and stucco terraces laid out for the Portman and Howard de Walden estates, including the Harley Street medical quarter and generous mansion flats, with a strong grain of Georgian townhouses converted to consulting rooms, offices and apartments.

Streets we regularly draw for in Marylebone

Harley Street · Margaret Street · Foley Street · Cleveland Street

What the wider borough is built of

W1U has too few classified residential buildings to publish a district figure of its own, so we do not estimate one. The measured figures below are borough-wide and W1U is not among the districts they cover.

Borough-wide building mix

Residential building form across 5 of the borough's 6 postcode districts, from 1,043 classified buildings. W1U is below the publication floor and is excluded from these totals, so they describe the borough around it rather than the district itself.

Attached on more than one side88%
Attached on one side9%
Detached2%
Buildings attached on more than one side921
Detached buildings26
Buildings classified1,043
Postcode districts measured5

Source: Ordnance Survey National Geographic Database (derived statistics). Contains OS data © Crown copyright and database right 2026. Contains Royal Mail data © Royal Mail copyright and database right 2026. Extracted 2026-08-17.

Planning Permission for Marylebone (W1U) homes: the package and the process

A householder application is refused validation far more often than it is refused permission, and almost always for the same reasons: a location plan at the wrong scale, no red line around the application site, a missing ownership certificate, or elevations that do not show every face of the building affected. We prepare the full submission set — location plan, block plan, existing and proposed floor plans, elevations and sections — so the case officer receives a complete case on day one.

Once the application is live we stay on it. Officers routinely come back with questions about materials, boundary treatment or a dimension they cannot read off the drawings, and a fast, drawn answer is usually the difference between a decision inside the statutory period and a request to withdraw and resubmit.

Which route applies is decided by the building before it is decided by policy. A house that has never been extended usually has allowances left to use; a flat, a listed building or a home in a conservation area often has none, and the same drawing set then has to make a design case rather than a compliance one.

Do I need planning permission for an extension in London?

Many single-storey rear extensions, loft conversions and outbuildings fall under permitted development rights and do not need a full planning application — but London's dense housing stock, conservation areas and Article 4 directions frequently withdraw those rights. Before you pay for a full application, we check your property against the current permitted development thresholds and your borough's local constraints.

Where permitted development applies, we recommend a Lawful Development Certificate instead of full planning — it is faster, cheaper and gives you a legal document confirming the work was lawful. Where a full application is genuinely required, we prepare it properly the first time.

Permitted development vs a full planning application

Permitted development lets you build within defined volumetric limits without committee review. A full householder application is assessed against the borough's local plan for scale, daylight, neighbour impact and design. We advise which route your project qualifies for and why.

Article 4 directions and conservation areas

If your home sits in a conservation area or under an Article 4 direction, permitted development rights are often removed — meaning even modest changes need consent. Each borough page lists the local directions and conservation areas we routinely design around.

How do you apply for planning permission through the London Planning Portal?

We manage the full lifecycle of your submission — survey, drawings, supporting documents and officer liaison — so you never have to decode a validation checklist yourself.

Phase 1 — existing and proposed site surveys

A laser-measured survey captures your property exactly, so existing and proposed drawings match reality millimetre for millimetre.

Phase 2 — technical drawing package

Site location plan, block plan, floor plans, elevations and sections drawn to your borough's scale and formatting requirements, with a design and access statement where needed.

Phase 3 — liaison with the planning officer

We answer the council's queries, negotiate amendments, and redraw free until the decision lands.

How long does planning permission take, and what does it cost?

Drawings are typically ready within 7 days of survey. Your council then has a statutory 8 weeks to decide a householder application. Our drawing fees are fixed and quoted upfront — the table below shows typical packages.

Typical fixed-fee planning drawing packages
PackageProduction windowCompliance layerTypical fee
Permitted Development pack7–10 working daysLawful Development Certificate submission£950–£1,450
Full Planning pack10–14 working daysCouncil liaison & design statement£1,600–£2,400
Planning + Building Regs pack14–21 working daysStructural calculations included£2,200–£3,850
Sheet from a planning permission package drawn for a Marylebone property in W1U, showing the existing and proposed arrangement at scale
A sheet from the planning permission package we submit to Westminster City Council for Marylebone (W1U) properties.
FAQ

Planning Permission in Marylebone W1U — FAQs

How long does it take to get planning permission from a London council?+
Householder applications carry a statutory 8-week determination period. We deliver your drawings within about 7 days of survey, so the council clock can start quickly. Lawful Development Certificates usually resolve faster.
What happens if the council refuses?+
Refusals are rare because every drawing is checked against your borough's local plan before submission. If it happens we advise on revisions or handle the appeal — many refusals recover at appeal.
Do you cover my borough?+
Yes — we submit across all 33 London boroughs every week. Each borough has its own page covering local conservation, Article 4 and validation quirks.
Is the fee really fixed?+
Yes. We quote a fixed fee before we start and it does not move, even when the council asks for revisions — those redraws are free.
Do I need planning permission for works in Westminster?+
Almost always. The great majority of Westminster falls within a conservation area and a high proportion of buildings are listed, so a full planning application — and often listed-building consent — is usually required even for modest works. Permitted development rarely applies. We screen conservation, listing and lease constraints for your address before recommending a route.
I live in a mansion block — what extra consent might I need?+
Much of Westminster's stock is mansion-block or garden-square terrace, and the lease frequently requires the freeholder's consent alongside planning for external alterations. We confirm the lease position early and design a scheme that satisfies both the freeholder and the council, since either can block an otherwise sound proposal.
Will I need a Basement Impact Assessment in Westminster?+
Usually, for below-ground works. The City Plan basement policy requires a basement impact assessment and limits scale. If you are considering a basement or lower-ground extension we flag the requirement early and coordinate the structural and drainage input so the application is complete when submitted.
How long does Westminster City Council take to decide?+
Westminster determines most householder applications within the statutory eight-week period once validated, though listed-building, basement and conservation cases frequently attract additional consultation. We prepare submissions to the council's exacting validation and design standards to avoid the drawing queries that cause most delays.
How much do planning drawings cost in Westminster?+
We agree a fixed fee before we start, typically around 30% below an architect's fee for the same council-accepted drawings, with free redraws until the council approves. Heritage-led, listed-building and basement schemes require more evidence than a standard extension, so we quote once we understand your address and scheme rather than by the hour.
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