TL;DR
HMRC is consulting on plans to widen its Uncertain Tax Treatment regime to wealthy individuals and trusts claiming tax advantages of more than £5 million. The regime currently applies to large businesses. A consultation is a proposal stage: no change has taken effect yet.
Last reviewed: 14 May 2026
Key facts
- HMRC is consulting on extending the Uncertain Tax Treatment regime.
- The proposed extension covers wealthy individuals and trusts.
- It would apply where claimed tax advantages exceed £5 million.
- The regime currently applies to large businesses.
- A consultation is a proposal: nothing has changed in law yet.
What HMRC is proposing
HMRC has opened a consultation on plans to widen its Uncertain Tax Treatment regime so that it also covers wealthy individuals and trusts that claim tax advantages of more than £5 million. The consultation was reported in mid-May 2026.
What the Uncertain Tax Treatment regime is
The Uncertain Tax Treatment regime requires affected taxpayers to notify HMRC when they adopt a tax treatment that is uncertain, broadly where their position differs from HMRC's known interpretation of the law. It is a disclosure mechanism designed to give HMRC earlier visibility of contentious tax positions. At present it applies to large businesses above set size thresholds.
Who would be affected if it proceeds
The proposed extension is aimed at wealthy individuals and at trusts, in cases where the tax advantage claimed from an uncertain treatment exceeds £5 million. That threshold means the measure is targeted at a narrow group of high-value arrangements rather than at taxpayers generally.
Why HMRC is consulting
Extending notification requirements gives HMRC earlier sight of high-value uncertain positions taken outside the corporate sector. The stated direction of this kind of measure is to reduce the tax gap by surfacing contentious treatments sooner, rather than discovering them only through later enquiry.
What happens next
Consultations run for a defined period during which interested parties can respond. HMRC then publishes a response and, if it proceeds, draft legislation follows before any change takes effect. Affected taxpayers and their advisers typically review consultation documents to understand scope and timing.
What to watch
Key points to follow are the consultation closing date, HMRC's published response, and any draft legislation, which would set out the precise definitions, thresholds and commencement. Until then the regime continues to apply only to large businesses.
Frequently asked questions
Has the Uncertain Tax Treatment regime been extended?
No. HMRC is consulting on extending it. A consultation is a proposal stage and does not change the law.
Who would the extension cover?
Wealthy individuals and trusts claiming tax advantages of more than £5 million from an uncertain tax treatment.
Who does the regime apply to now?
At present it applies to large businesses above set size thresholds, which must notify HMRC of uncertain tax treatments.
What is an uncertain tax treatment?
Broadly, a tax position that differs from HMRC's known interpretation of the law. The regime requires affected taxpayers to notify HMRC when they adopt one.
When could any change take effect?
No date is set. Any change would follow the consultation response and draft legislation. The timing depends on that process.
