What planning rules in City of London catch homeowners out?

The City of London covers barely a square mile, but its planning rules are some of the most intricate in the country. Most homeowners assume their project is straightforward — until they discover that almost nothing here works the way it does elsewhere.

Conservation areas cover almost everything

In most London boroughs, conservation area status applies to certain streets or neighbourhoods. In the City of London, it applies to nearly everywhere. That single fact changes the planning picture dramatically — and most homeowners don't realise how much until they've already committed to a project.

Being in a conservation area doesn't just mean you need to be careful about aesthetics. It affects what work is even permitted without a formal application, what the City Corporation will scrutinise, and how detailed their design guidance becomes. Each conservation area also has its own specific guidance published by the City Corporation. Whether your property sits in one zone or another — even on the same street — can determine whether your project is straightforward or deeply complicated.

The best way to understand what your property's conservation area status actually means for your specific plans is to find out how your property's constraint combination affects your planning odds.

Listed buildings — and the consent you might not know you need

The density of listed buildings in the City of London is extraordinary. Centuries of architectural history are compressed into a tiny area, and listed building coverage here is far higher than in most London boroughs.

Here's what catches people out: if your property is listed, or if it's been altered at some point using materials or methods connected to a listed structure, almost any external change — and many internal ones — requires listed building consent. That's a completely separate consent from planning permission. You can have one without the other, and needing both means two applications, two fee payments, and two separate decision timelines.

Most homeowners don't realise their property is listed until they're already mid-project. And the consequences of works carried out without listed building consent are serious.

Permitted development rights are not what you'd expect

Elsewhere in England, permitted development rights allow homeowners to carry out a range of common works — certain extensions, loft conversions, outbuildings — without a formal planning application. In the City of London, the combination of conservation area status, listed building designations, and the dense commercial context means those rights are far more restricted than most people assume.

The rules around what's permitted and what requires a full application shift depending on your specific property, its listing status, its position within a conservation area, and its use history. Two properties on the same street can face entirely different requirements. The City Corporation also maintains detailed design guidance that adds another layer of expectation on top of the standard national framework.

Before assuming any external alteration is fine, it's worth knowing what's actually been approved and refused on properties like yours nearby. WhatCanIBuild lets you see what similar projects on your street got approved or refused — no signup needed, takes about a minute.