UK HMRC Privilege Dispute Rules Start on 19 June 2026

Tax rules often arrive in language that feels built to keep ordinary readers out. This new HMRC regulation is worth slowing down for, because it answers a practical question: what happens if HMRC demands information, but you say some of it is protected by legal privilege? The Anti-avoidance Information Notices (Resolution of Disputes as to Privilege) Regulations 2026 were made on 27 May 2026, laid before the House of Commons on 29 May 2026, and come into force on 19 June 2026. As the text published on legislation.gov.uk shows, the rules are about procedure. They do not create privilege from scratch; they explain how a dispute about privilege is sorted out after HMRC issues an anti-avoidance information notice.

To see why this matters, it helps to start one step earlier. Under sections 179 to 183 of the Finance Act 2026, HMRC can issue anti-avoidance information notices to ask for information or documents while checking suspected tax avoidance arrangements. The Act uses a broad idea of information here: it can include a document, part of a document, or anything in which information is recorded. But HMRC cannot simply demand everything. The Finance Act 2026 says some material is excepted information, including privileged information. In everyday terms, that usually means certain confidential communications with a lawyer. **What this means:** the argument is not about whether HMRC may investigate in general. It is about whether particular material should stay private.

The new Regulations say the first move sits with the recipient of the notice, or with somebody acting on their behalf, such as an adviser. If they think some of the requested material is privileged, they must serve HMRC with a list of the items in dispute. That list has to identify the information being withheld and describe the material and its contents. There is an important safeguard here. If even describing the material would itself reveal privileged information, the recipient does not have to give that description. That may sound like a small drafting point, but it matters. A rule that forced you to disclose privileged content just to defend privilege would cancel out the protection.

Timing matters just as much as the legal argument. The disputed list must reach HMRC by the date given in the information notice, unless HMRC agrees a later date. Even then, the extension is limited. The later date must still fall within 20 working days beginning on the day after the original deadline. The Regulations also define a working day carefully. It means any day other than a Saturday, Sunday or bank holiday in any part of the United Kingdom. If you are reading this as a student, business owner or adviser, that detail is not filler. In tribunal procedure, deadlines can decide what happens next.

Once HMRC receives the list, it must tell the recipient which of the disputed items it thinks are not privileged. If there is still disagreement after that, the next step is formal. The recipient must apply to the tribunal to resolve the dispute. That application has its own deadline. It must be made within 20 working days beginning on the day after HMRC gives its notification. The application must also include copies of the material still in dispute. In other words, the tribunal is not deciding in the abstract. It can examine the information itself before ruling on whether privilege applies.

This is where the Regulations offer some breathing space. If the steps have been followed properly, the recipient is treated as having complied with the information notice in relation to the disputed material while the disagreement is being sorted out. That protection lasts until the tribunal decides the status of the information, or until HMRC and the recipient reach a written agreement. The tribunal's role is narrow but important. It may confirm whether, and to what extent, the information is privileged. **Why that matters:** you do not lose your position simply because HMRC disputes your claim on day one. The rules create a temporary holding position while an independent body decides.

There is also room for agreement before a hearing. Regulation 5 says HMRC and the recipient can settle the dispute at any time in writing. So although the tribunal is the formal referee, not every privilege argument has to end there. For most readers, the bigger lesson is about balance. HMRC wants access to information when it believes tax avoidance may be involved. Taxpayers and advisers may need to protect confidential legal material. These Regulations set out a clearer route between those two positions: identify the disputed material, meet the deadlines, and if agreement is not possible, let the tribunal decide. The explanatory note says a Tax Information and Impact Note published alongside the 26 November 2025 Budget remains an accurate summary of the instrument's effects. From 19 June 2026, though, this stops being a plan on paper and becomes the live rulebook for these disputes.