Tree Preservation Orders and Planning in London: What Protected Trees Mean for Your Extension

What is a Tree Preservation Order?

A Tree Preservation Order, or TPO, is an order made by a local planning authority under the Town and Country Planning Act 1990 that protects a specific tree, group of trees or woodland. Once a tree is covered by a TPO it is a criminal offence to cut it down, top, lop, uproot, wilfully damage or wilfully destroy it without the council's written consent. The protection covers the whole tree, including its roots, so damage caused by trenching for a foundation counts just as much as cutting a branch.

Councils make TPOs where a tree brings amenity value to an area — visible from a public place, contributing to the character of a street, or valuable for its rarity, age or screening. In London this is common on Victorian and Edwardian streets where mature street and garden trees define the setting. A TPO can be served quickly and takes provisional effect immediately, so a tree you assumed was unprotected can gain protection at any time. This is why you check the position before you design around removing or pruning a tree, never after.

How do I check if a tree is protected in London?

Check the council's TPO register first. Every London borough keeps a record of the Tree Preservation Orders it has made, and most now publish an online map or searchable register where you enter your address and see any orders affecting your plot or a neighbour's. If the map is unclear, the council's tree or arboricultural officer will confirm the status of a specific tree in writing, and that written confirmation is worth having on file before you commission drawings that rely on removing or reshaping the tree.

Two separate checks matter, because a tree can be protected in two different ways. First, is the tree subject to a TPO? Second, does the site fall within a conservation area, in which case the tree is protected regardless of any TPO? A single London garden can easily sit inside a conservation area while also containing a specifically TPO'd tree, and each protection carries its own consent or notice process. Getting both answers before you finalise a footprint saves an expensive redesign later.

Do I need consent to prune or fell a protected tree?

Yes. For a tree covered by a TPO you must apply to the council for consent before any pruning, topping, lopping or felling, and you cannot begin works until that consent is granted. The application is free, and you set out exactly what you propose to do and why, usually supported by an arboriculturist's report where the works are significant. The council can grant consent, grant it with conditions such as replanting, or refuse it, and there is a right of appeal to the Planning Inspectorate if you disagree with the decision.

For a tree in a conservation area that is not separately TPO'd, the route is different: instead of applying for consent you give six weeks' written notice of the proposed works. If the council does nothing within that period you may proceed, but if it makes a TPO in response you must then apply for consent as above. There is a narrow exemption for dead trees and for cutting back to remove an immediate danger, but the safe course is always to document the condition and notify the council rather than rely on an exemption you may be unable to prove later.

• TPO tree — apply for written consent and wait for the decision before any works begin
• Conservation-area tree — give six weeks' written notice, then proceed only if no TPO is made
• Dead or dangerous trees — a limited exemption applies, but record the evidence and notify the council first
• Replanting conditions — consent to fell often comes with a duty to plant a replacement tree

How do protected trees and Root Protection Areas affect my extension?

This is where trees most often reshape a London project. Every tree has a Root Protection Area, or RPA, defined in British Standard BS5837:2012 as a notional circle whose radius is calculated from the trunk diameter — twelve times the stem diameter for a single-stem tree, capped at 707 square metres. Building within the RPA risks severing the structural roots the tree depends on, so where your proposed foundations fall inside it the council will resist the scheme unless you can prove the tree can survive. A protected tree in or near your garden can therefore dictate how far your extension can reach.

The usual solutions are to pull the footprint back outside the RPA, or, where that is impossible, to design special no-dig or piled foundations that span the roots without excavating through them. These decisions belong at the drawing stage, not on site, because they change the structural design and the cost. Good planning drawings show the tree, its RPA and the protective fencing on the site plan from the outset, which is exactly the coordination that gets an extension approved near a protected tree rather than refused over root damage.

When is an Arboricultural Impact Assessment required?

Where a London planning application affects, or is close to, a protected or significant tree, the council will almost always require an Arboricultural Impact Assessment prepared to BS5837. This is a report by a qualified arboriculturist that surveys each relevant tree, categorises it by quality, plots the Root Protection Areas onto your drawings, and assesses how the proposal affects each tree during and after construction. It is typically accompanied by a Tree Protection Plan and an Arboricultural Method Statement setting out the fencing, ground protection and working method that keep the retained trees safe.

Submitting this alongside the planning drawings does two things. It demonstrates to the officer that the trees have been properly considered, which removes a common reason for delay or refusal, and it defines the construction constraints your builder must follow. In the denser, tree-lined boroughs an application that ignores an obvious protected tree is often held at validation until the assessment is provided, so it is far cheaper to commission it up front than to be asked for it mid-determination when your eight-week clock is already running.

What are the penalties for unlawful felling?

The penalties are severe and are among the few planning offences that regularly reach the criminal courts. Cutting down, uprooting or wilfully destroying a protected tree, or damaging it in a way likely to destroy it, can be prosecuted with a fine of up to £20,000 in the Magistrates' Court, and in the Crown Court the fine is unlimited. Courts are directed to take account of any financial benefit the offender gained — for example the uplift in a plot's value from removing a tree that blocked a development — so the penalty can be set deliberately high to remove that gain.

Enforcement does not stop at the fine. Where a protected tree is removed, whether unlawfully or with consent to fell, a statutory duty to plant a replacement tree of an appropriate size and species usually arises, and that replacement itself becomes protected by the original order. The council can serve a notice requiring the replanting, and failing to comply is a further offence. In short, felling a protected tree to make room for an extension is never a shortcut — it exposes you to prosecution, an unlimited fine and a legal obligation to replant.

How do TPOs and conservation-area protection compare?

Both regimes protect trees, but they work differently, and knowing which applies to your tree tells you exactly what step to take before works. The table below sets out the practical differences a London homeowner needs.