If your overseas company has staff, a contract signer, or just a desk in the UK, you may already have a UK permanent establishment — and a UK Corporation Tax liability — without anyone at head office realizing it. The rules that decide this are not about where the company is incorporated. They are about what actually happens on the ground in the UK, and HMRC’s definition of a “fixed place of business” or “dependent agent” is wider than most overseas boards expect.
This guide explains what a permanent establishment (PE) is under UK domestic law and under tax treaties, when trading with the UK tips over into trading in the UK, and what a UK PE actually means for Corporation Tax.
Key Takeaways
A non-UK resident company has a UK permanent establishment if it has a fixed place of business here through which its business is wholly or partly carried on, or if someone habitually concludes contracts here on its behalf.
A non-UK resident company only comes within UK Corporation Tax on its trading income if it trades in the UK through a permanent establishment — simply trading with UK customers from abroad does not create a charge. UK land dealing or development, and UK property income, are taxed here regardless of any UK presence.
Genuinely preparatory or auxiliary activity — storage, display, delivery, or pure information-gathering — does not create a PE, but the exemption is switched off where the activity is part of a deliberately fragmented business operation.
Where a double taxation treaty applies, its terms take precedence over UK domestic law. Since UK domestic law adopted a wider dependent-agent test from January 2026 while most UK treaties still use the older wording, a treaty can genuinely change the answer in agent cases — it is not a formality to skip.
Where a UK PE exists, only the profits it would have made as a separate, independent enterprise dealing at arm's length with the rest of the company are taxed in the UK.
What Is a Permanent Establishment for Tax Purposes?
A permanent establishment is the test that decides whether a non-UK resident company’s presence in the UK is substantial enough to bring its trading profits within the UK Corporation Tax net. Under section 1141 CTA 2010, a company has a permanent establishment if either of two tests is met:
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It has a fixed place of business here through which the business is wholly or partly carried on; or
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A person acting on its behalf habitually concludes contracts, or habitually plays the principal role leading to contracts that are routinely concluded without material modification.
These are two genuinely different routes into a PE, and groups often only think about one of them. The first is a fixed place of business. The obvious examples are a place of management, branch, office, factory, workshop, or building site. But it can also be less obvious things — a home office or shared workspace in the UK, for instance, if the same person keeps using it on a regular basis to carry out the company’s business. The second is a dependent agent, which needs no UK premises at all. This route catches UK-based sales staff, country managers, or distributors who aren’t genuinely independent — people who habitually negotiate and finalize deals that head office simply rubber-stamps.
Not every UK footprint counts, though. Activity that is genuinely preparatory or auxiliary to the company’s business as a whole — storage, display or delivery of the company’s own goods, or pure purchasing and information-gathering — falls outside the PE tests. HMRC’s own example is a market research company whose UK staff collect market data: because that activity is the company’s actual trade, it is not preparatory or auxiliary, even though “collecting information” appears in the statutory list. There’s also an anti-fragmentation rule sitting behind this exemption: it doesn’t apply where a business operation is deliberately split across UK locations or closely related entities so that each piece looks preparatory or auxiliary on its own, even though the combined activity is not.
Picture a group that runs a UK warehouse through one company and a UK sales team through a closely related one — neither piece looks like a full trade alone, but together they are. The rule looks past that split and asks what the combined UK activity actually amounts to; if it goes beyond preparatory or auxiliary, the exemption is denied to all of it.
Trading With the UK vs Trading in the UK
This distinction is the single most important concept in this area, and it is the one overseas groups most often get wrong.
Trading with the UK means selling into the UK market from abroad — taking orders from UK customers, shipping from an overseas warehouse, or delivering services remotely — without any UK fixed place of business or dependent agent involved in concluding contracts. This does not create a UK PE, and the profits stay outside the UK Corporation Tax charge.
Trading in the UK means the trade itself, or a meaningful part of it, is carried on from a UK base — a UK office negotiating and concluding deals, UK staff performing the core service, or a UK warehouse doing more than passive storage. Once that is the case, the company comes within the charge on the profits attributable to that UK presence.
The line is fact-specific. A UK-based employee who only gathers information or passes leads to head office for approval is likely still “trading with” the UK. The same employee negotiating final terms that are routinely rubber-stamped has probably tipped the company into “trading in” the UK.
Permanent Establishment Risk
Permanent establishment risk is the possibility that ordinary commercial activity inadvertently crosses the PE threshold — not through any deliberate decision, but simply through how a company grows its UK presence. The activities that most commonly create unplanned exposure include:
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A UK-based salesperson or country manager who effectively finalizes deals, even if someone abroad signs off
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A senior executive relocating to, or spending extended periods in, the UK
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A UK warehouse or fulfillment operation that does more than passive storage
One arrangement deserves particular attention here: using an Employer of Record (EOR) to place staff in the UK without setting up a UK entity. This is a common way to test the market, but it doesn’t remove PE risk by itself.
An EOR changes who is the legal employer, for payroll and immigration purposes. It doesn’t change what the person actually does day to day. If that person has — and habitually uses — authority to negotiate and conclude contracts, the overseas company can still have a UK PE, regardless of who issues the payslip.
The EOR itself is usually fine. A genuine third-party EOR, acting for many clients in the ordinary course of its own business, will typically qualify as an independent agent. The risk sits with the worker’s role and authority, not the payroll mechanism used to engage them.
Does the Treaty Save You?
Where the UK has a double taxation treaty with the territory in which the parent is resident, that treaty’s terms take precedence over the corresponding domestic provisions — so a company can rely on whichever test, domestic or treaty, works better for it. Most UK treaties define permanent establishment along the lines of Article 5 of the OECD Model Tax Convention, an international model definition that most countries use as a starting point. That definition was updated in 2017 specifically to close a loophole — some businesses had structured their UK agents narrowly on purpose, so that on paper the agent never technically “concluded” a contract, even though they did everything else needed to make the sale (these were often called “commissionaire” structures).
UK domestic law adopted this wider, 2017 version of Article 5 from 1 January 2026 — but most of the UK’s actual treaties were never updated to match, and still use the older, narrower wording. The result is that, for dependent agent cases, UK domestic law now catches more than most UK treaties do: a company that fails the domestic test can still be protected if a treaty applies and uses the older wording, so a treaty can genuinely change the answer here and is worth checking properly rather than assumed to add nothing. A treaty can also help where it sets a specific time threshold not mirrored in domestic law — many treaties, for instance, allow a construction site a period (commonly around twelve months) before it becomes a PE. Relying on a treaty without reading the actual article — in either direction — is one of the more expensive mistakes we see.
What Happens if You Do Have a UK PE
Once a non-UK resident company is found to have a UK permanent establishment, the company becomes chargeable to UK Corporation Tax on the profits attributable to the PE — but not on its worldwide profits generally. The PE is treated as if it were a separate, independent enterprise dealing at arm’s length with the rest of the company, taking into account the functions performed, assets used and risks assumed through the UK presence versus the rest of the business — the UK’s implementation of the OECD’s Authorized Approach to profit attribution.
A UK PE pays Corporation Tax at the same main rate as a UK resident company, and files a UK Company Tax Return (CT600) in the same way. One difference worth knowing: the 19% small profits rate and marginal relief are only available to UK resident companies, so a UK PE pays the 25% main rate however small its UK profits are — unless a relevant treaty’s non-discrimination article says otherwise. Beyond that, there is no separate, harsher regime just because the business happens to be run through a UK branch rather than a UK subsidiary.
Branch vs UK Subsidiary
Overseas groups entering the UK generally choose between a branch (a UK permanent establishment of the overseas company itself) and a UK subsidiary. A branch keeps the overseas company as the trading entity, taxed only on the profits attributable to the UK PE; it also needs to be registered as a UK establishment at Companies House, with its own filing obligations. A UK subsidiary is a separately incorporated UK-resident company, taxed on its worldwide profits by virtue of its residence rather than any PE analysis, with the benefit of separate legal identity and limited liability. Groups often prefer a subsidiary for liability ring-fencing and commercial credibility, even where a branch would give a broadly similar day-one tax result, because incorporating a UK company sidesteps the PE debate entirely.
Compliance: Registration
How a UK PE registers depends on how it arises. A branch or other UK establishment of an overseas company is usually registered at Companies House, and that registration also brings the company onto HMRC’s radar for Corporation Tax. Where the only UK presence is a dependent agent, with no branch or premises to register at Companies House, the company must register for Corporation Tax directly with HMRC instead. Either way, HMRC posts a Corporation Tax Unique Taxpayer Reference to the company’s overseas registered office — registration is generally dealt with within 15 working days, but postal delivery can take two to eight weeks — before the company can set up HMRC online services and file its return.
Overseas Permanent Establishment of a UK Trade
The same question runs the other way for UK companies with an overseas presence. A UK resident company is normally taxed on its worldwide profits, including those of any overseas branch. Under the current rules, a UK company can elect to exempt the profits (and losses) of its foreign permanent establishments from UK Corporation Tax altogether, so those profits are taxed only in the overseas territory — attractive where the overseas tax rate is comparable to or higher than the UK rate, though the election is irrevocable and applies to all of the company’s foreign PEs at once, not on a country-by-country basis — so it needs careful modeling before it is made, including the effect of losing UK relief for any overseas branch losses.
This is changing. The government has confirmed that the exemption will become mandatory rather than elective, for accounting periods beginning on or after January 1, 2027 (September 1, 2026 for oil and gas companies). From that point, a company will no longer have the choice — both the profits and the losses of its foreign PEs will automatically sit outside UK Corporation Tax.
Permanent Establishment vs VAT Fixed Establishment
It is a common mistake to assume a direct tax permanent establishment and a VAT fixed establishment are the same thing — they are not, and a company can have one without the other, so a VAT registration (or the lack of one) does not settle the Corporation Tax question. A permanent establishment asks whether the trade itself is being carried on from the UK. A VAT fixed establishment asks a narrower question: whether the UK location has enough people and equipment, on a lasting basis, to receive or supply the services in question. Each is assessed on its own facts, under its own rules.
Common PE Mistakes We See
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Assuming a job title or engagement type — "sales representative," "EOR employee," "independent distributor" — settles the question, when what matters is the authority actually exercised.
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Splitting a UK operation across two group entities on the assumption that each piece looks preparatory or auxiliary in isolation.
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Assuming a double taxation treaty adds nothing without checking its actual wording — since January 2026, UK domestic law is wider than most UK treaties for dependent agent cases, so a treaty can now genuinely change the answer.
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Confusing VAT fixed establishment status with Corporation Tax PE status, or letting one answer stand in for the other.
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Leaving HMRC registration until a filing deadline is close, without allowing for the postal timelines involved.
Worked Example: A SaaS Company Building UK Sales Presence
A US-incorporated SaaS company hires a UK-based Head of Sales. She works from home, attends prospect meetings, negotiates commercial terms including discount levels, and her signed order forms are routinely approved by the US CFO without material change. There is no UK office and the company does not think of itself as “in” the UK.
This pattern — UK-based negotiation with routine, unmodified sign-off elsewhere — is exactly the kind of fact set the dependent agent test is aimed at, and the absence of a physical office does not put it outside scope. Whether it actually crosses the line depends on the precise scope of her authority and how deals are approved in practice, which is a judgment call on the specific facts rather than something a general description can settle.
Worked Example: A Manufacturing Group's UK Warehouse
An EU manufacturer stores finished goods in a third-party UK warehouse purely for onward delivery to UK customers who order and pay from the group’s EU sales office. No UK staff negotiate terms; the warehouse operator has no authority to conclude contracts.
On the face of it, this sits closer to the preparatory or auxiliary exemption than to a PE — storage and delivery of the company’s own goods, for a business whose core trade is manufacturing and selling rather than warehousing. But the fragmentation rule means the answer can flip if the arrangement sits alongside other UK activity carried out by the same or a closely related entity, or if the warehouse’s role extends into assembly, customization, or local sales input — which is why arrangements like this are worth revisiting whenever the UK operation grows or changes shape.
Frequently Asked Questions
A permanent establishment is the tax test; a branch is one common way of satisfying it. A UK branch will typically be a PE, but a PE can also exist without any branch at all — for example, through a dependent agent with no UK premises.
There is no way to “avoid” PE risk while genuinely running commercial UK activity, since the tests apply to substance rather than labels. Risk is generally lower where UK activity stays clearly on the preparatory-or-auxiliary side of the line and where UK-based people and entities are genuinely independent. Where the answer isn’t clear-cut, it needs assessing against the specific facts before UK headcount or premises grow, not after.
Nothing needs to be applied for or registered in advance — a PE arises the moment the underlying facts meet either test, which is exactly why it is so often missed until HMRC, an auditor, or a due diligence exercise looks at what is actually happening on the ground.
This is not a distinct legal test. It generally refers to the practical question of whether an overseas employer with UK-based staff or a UK PE needs to operate PAYE and National Insurance on those employees’ earnings — a payroll compliance question that sits alongside, but is legally separate from, the Corporation Tax PE analysis.
A UK PE is brought within Corporation Tax on the profits attributable to it, and may separately need to consider VAT under its own fixed establishment test, employer PAYE and National Insurance if it has UK staff, and the transfer pricing rules governing its dealings with the rest of the company.
The Conclusion: What You Need to Do Now
If your overseas company has any UK-based individual negotiating deals, any UK premises used for more than pure storage or display, or a UK subsidiary that habitually finalizes contracts on your behalf, the permanent establishment question needs answering now, not at the point HMRC raises it.
This is not a test that can be answered from a generic checklist. Whether a fixed place of business or dependent agent PE exists turns on the precise facts of how contracts are actually negotiated and concluded, how UK premises are actually used, and how the relevant treaty is worded — all of which need to be checked against your actual structure.
Getting the PE analysis wrong in either direction carries real cost: understating a PE means an unregistered Corporation Tax liability, potential penalties, and a rushed filing process once discovered; overstating one — or over-restricting a genuinely low-risk UK sales presence out of caution — can mean giving up a UK market opportunity unnecessarily.
How Can We Help
If you need to establish whether your overseas company’s UK activity has created, or is at risk of creating, a UK permanent establishment, we can review your actual UK footprint against the domestic and treaty tests and give you a considered view before it becomes an HMRC inquiry.
Our team will map your UK-based staff, agents and premises against the fixed-place-of-business and dependent-agent tests, check the relevant double taxation treaty where one applies, and confirm whether any UK activity is protected by the preparatory-or-auxiliary exemption. Where the analysis points toward a PE, we can also help you register with HMRC and, if relevant, Companies House, and work through profit attribution under the separate enterprise principle.
