HMRC lawyer declaration rules in tax avoidance cases
On 23 June 2026, a new HMRC regulation comes into force with a long name but a fairly specific job. The legislation.gov.uk text says Statutory Instrument 2026 No. 570 sets the rules for declarations made by lawyers when they are trying to stop HMRC from publishing information about a tax avoidance scheme. If that already sounds technical, here is the plain-English version. This is not a law that creates a brand new anti-avoidance power. It is a law about evidence and process. It explains what a lawyer must tell HMRC if they want to say, 'privileged communications prove our case, but we cannot show you those communications directly.'
The background matters. As the explanatory note says, HMRC already has powers under the Finance Act 2004, the Finance (No. 2) Act 2017 and the Finance Act 2022 to publish information about tax avoidance schemes, including naming a person. That is a serious public power, because publication can affect reputation as well as enforcement. Before HMRC publishes, the person concerned can make representations arguing that publication should not happen. These 2026 regulations sit inside that process. They tell lawyers what a declaration must contain if legal professional privilege, or in Scotland confidentiality of communications, means the supporting legal material cannot simply be handed over.
**What legal professional privilege means:** in broad terms, it protects confidential lawyer-client communications from being disclosed. That protection matters because people must be able to seek legal advice honestly. But it also creates a problem when HMRC asks for proof and the proof sits inside privileged material. Section 209 of the Finance Act 2026 is the answer Parliament chose. It lets a lawyer declare that privileged communications would back up the representations without waiving privilege. In other words, the lawyer is being asked to stand behind the substance of the claim, even though the underlying advice stays protected.
The regulations are exacting about what must go into that declaration. According to the legislation.gov.uk text, it must name the lawyer who intends to make the representations, the lawyer who signs the declaration if that is a different person, and any other lawyer whose privileged communications are being relied on. It must also give each named lawyer's home address and practising address. That personal detail is striking, and it shows how formal this process is meant to be. The declaration must also name each professional regulator for those lawyers and, where relevant, include the identifying number issued by that regulator. HMRC is not being asked to accept an anonymous or vague assurance.
The declaration must then pin down the substance of the dispute. It has to identify the arrangements in question, identify each fact in the representations that the declaration relates to, and say whether the privileged communications on their own are enough to show, on the balance of probabilities, that those representations are true. If the privileged communications are not enough on their own, the declaration must identify the other information being relied on alongside them. **What 'balance of probabilities' means:** this is the ordinary civil test. It asks what is more likely than not, rather than requiring proof beyond reasonable doubt. So the regulation is not only about who signs the paperwork. It is also about the standard of proof the lawyer is saying can be met.
The final steps are about accountability. The lawyer making the declaration must confirm that its contents are true to the best of their knowledge and belief, and must sign and date it. The timing rule matters too: the declaration has to reach HMRC no later than the representations themselves. You cannot send the argument first and the supporting declaration later. From HMRC's point of view, that makes the process tighter and harder to abuse. From a fairness point of view, you can also see the logic: if privileged material is going to be relied on as part of a challenge to publication, HMRC wants a clear, contemporaneous record of who is saying what, and on what basis.
What changes for readers, firms and advisers is not the existence of privilege, but the shape of the paperwork around it. These regulations do not force lawyers to reveal the content of privileged advice. They do, however, require a detailed, traceable declaration if that privileged advice is being used to support a case against HMRC publication. That is a procedural rule with potentially big practical consequences in disputes about marketed tax avoidance. The instrument was made on 1 June 2026, laid before the House of Commons on 2 June 2026, and comes into force on 23 June 2026. The explanatory note says a Tax Information and Impact Note published on GOV.UK on 26 November 2025, alongside Autumn Budget 2025 material on tackling promoters of marketed tax avoidance, still accurately describes the impact. If you are watching how far HMRC's naming powers reach, this is the sort of technical rule worth noticing, because process often decides who gets heard and what can be safely said.