Knights Developments Limited v HMRC [2026] UKUT 329 (TCC), handed down on 25 August 2026, is not a Crown Dependency footnote. It is a source-state taxing-rights case with board-level consequences for any group that still treats “no UK permanent establishment” as a shield for UK land development profits. The Upper Tribunal (Mr Justice Nicholas Thompsell and Judge Swami Raghavan) dismissed the taxpayer’s appeal and upheld closure notices for roughly £5.4 million of UK corporation tax on trading profits from acquiring, developing and selling land at Knights Wood, Tunbridge Wells.
The structure looked carefully engineered. Knights Developments Limited (KDL) was Isle of Man resident, never UK resident, and HMRC accepted it had no UK permanent establishment. Strategic decisions stayed in Braddan. Construction and sales support sat with another IoM group company, Dandara Limited, that did operate through UK PEs. KDL disclosed the profits on UK CT returns and claimed treaty exemption. The UT still held that the UK could tax those profits under the immovable-property income article. Primary sources: the National Archives judgment, the full PDF, Bloomberg Tax’s report on the £5.4m outcome, and HMRC’s UK–Isle of Man treaty pack.
Why the numbers matter beyond one SPV
Returned/adjusted profits for the periods ending 30 June 2017 to 30 June 2021 totalled about £28.3 million. Closure notices sought additional CT of roughly £0.92m, £1.24m, £0.51m, £0.40m and £2.33m. KDL is the lead appeal for related Dandara-group companies stayed behind it. More important for the market: HMRC told the Tribunal that similarly situated parties could generate historic refund claims of up to £1 billion and future lost revenue of up to £230 million a year if the taxpayer’s reading had won. This is a revenue-map case, not a one-off assessment fight.
The parties agreed almost everything that usually clogs PE enquiries. KDL carried on a trade of dealing in and developing UK land. Profits were trading profits — income, not capital — under UK domestic law. Knights Wood land was trading stock and WIP. Physical build was contracted to Dandara Limited. Marketing sat under a 2014 agency-style arrangement with 1.5% commission, but KDL’s IoM officers approved every material commercial step, including offers before exchange. The only live issue was treaty allocation of taxing rights.
Domestic charge first: FA 2016 did its job
After Finance Act 2016 s76, CTA 2009 s5(2)(a) brings a non-UK resident company into the CT charge if it carries on a “trade of dealing in or developing UK land”. Section 5(2A) charges that company on all profits of that trade wherever arising. Section 5B defines the trade to include dealing in UK land and developing UK land for disposal. HMRC’s line is in BIM60510 and BIM60530. Part 8ZB CTA 2010 deeming was discussed but not needed — the parties agreed KDL had an actual trade.
Domestic law already said “taxable”. The fight was whether the UK–Isle of Man arrangements still carved the profits out because there was no PE and the profits were business profits under the business-profits article. That is the classic offshore developer thesis: residence jurisdiction taxes lightly or not at all, source is blocked by PE rules, and UK land still funds the group. Knights kills the clean version of that thesis under the post-2016/2018 treaty text.
The treaty question
Two instruments mattered. The 2016 Protocol inserted paragraphs 3A and 3B into the old 1955 arrangements. The 2018 UK–Isle of Man Double Taxation Agreement then replaced that framework with OECD-model Articles 6 and 13 for later periods. The parties treated the interpretative questions as materially the same. Article 7 still said enterprise profits are taxable only in the residence territory absent a PE — and HMRC did not contest “no PE” for KDL. Article 7(4) preserves separate articles where they apply. The hierarchy fight was simple: do development-and-sale trading profits sit in Article 6 (source can tax), Article 13 (source can tax gains from alienation), or only Article 7 (residence only, no UK tax)?
KDL argued Article 6 is confined to income from the use or exploitation of land while ownership continues, and that Article 6(3) (“direct use, letting, or use in any other form”) exhaustively defines “income derived”. Alienation, they said, belongs if anywhere in Article 13 — and Article 13, after OECD structure and Royal Bank of Canada reasoning discussed in the judgment, is about capital gains, not trading profits. No PE, no Article 6, no Article 13 → IoM only. HMRC’s case was that Article 6(1) is broad; paragraph (3) clarifies rather than closes the class; paragraph (4) keeps enterprise income from immovable property in Article 6 even without a PE.
What the Upper Tribunal held
- Article 6(1) is the operative rule. “Income derived … from immovable property” is general. A trader who acquires land, improves it and realises profit on sale derives that profit from the property in a direct and substantial sense. Nexus is required; ongoing ownership after realisation is not.
- Article 6(3) is clarificatory, not exhaustive. It is not drafted as a definition. Reading it as a closed list would gut paragraph (1).
- Article 6(4) reinforces breadth. Immovable-property income of an enterprise stays out of the PE-gated business-profits box.
- OECD Commentary and reservations do not force a use-only reading. Commentary is persuasive, not a hard outer fence.
- Article 13 was HMRC’s fallback and would have failed on principle. Had it been necessary, the UT would have held Article 13 concerns capital gains, not trading profits merely because they arise on disposal. KDL still lost because Article 6 already caught the profits.
Net: trading profits of a non-resident UK land developer can be UK-taxable under the immovable-property income article even with no UK PE and even where the group keeps strategic control offshore.
Why CFOs and PE tax leads should care this week
Treaty language is not PE language. Boards that signed off IoM or Channel Islands holdcos on a “no PE / business profits only” memo need that memo rewritten against Article 6, not just Articles 5 and 7. Agency and design-and-build separation is not a silver bullet — KDL did not build; Dandara did; KDL still took the development profit on trading stock. Disclosure-plus-exemption is high-stakes — cleaner than non-disclosure, but it tees up closure notices when HMRC disagrees. Group contagion is real — lead-case status plus HMRC’s £1bn / £230m pa framing means inventory every non-resident land-dealing entity with UK sites now, not after a personalised enquiry letter.
The control stack to lock now
- Entity map — every non-UK resident company with UK land dealing, development, option, promotion or land-banking activity, including title-only SPVs with a PE sister builder.
- Treaty memo refresh — which DTA applies, which periods sit under the 2016 Protocol vs the 2018 DTA, and whether the live defence is Article 6, Article 13, PE attribution, or something else. Kill pre-2016 PE-only advice.
- Profit characterisation — trading stock vs investment; income vs capital; Part 8ZB risk; transfer pricing on design-and-build, agency commission and group recharge.
- Governance evidence — where decisions are taken, who approves offers, who executes sales, and what agency agreements actually authorise. PE analysis still matters for other articles; it is not a complete exit from Article 6 on these facts.
- Enquiry and provision posture — if returns still claim treaty exemption on UK land development profits, quantify CT, interest and related-company contagion for audit committee before year-end.
- Deal diligence — buyers of UK residential platforms need tax covenant language on non-resident developer CT and open-year treaty positions, not generic “all CT paid” comfort.
Practical takeaway
Knights Developments does not say every offshore structure around UK property fails. It says something narrower and more useful: under the UK–Isle of Man arrangements as amended and replaced, income from UK immovable property includes trading profits from developing and selling that property, and that article can apply to an enterprise without a UK PE. If your tax model still equates “no PE” with “no UK CT on UK land development profits,” the model is wrong for this treaty family — and HMRC has now won that point at Upper Tribunal level with a published lead case and a very large revenue narrative attached.
Read the judgment, not the headline. Then open the entity map. The expensive mistake is waiting for your own closure notice before testing whether Article 6 already answers the question.
Sources: [2026] UKUT 329 (TCC); judgment PDF; Bloomberg Tax; HMRC IoM treaties; 2018 DTA; CTA 2009 s5; FA 2016 s76; BIM60510; CTA 2009 s5B; BIM60530.