The UK Is Now Criminalising Tax Planning Advice

Part 6 of the Finance Act 2026 crosses a constitutional boundary between punishing dishonesty and punishing an opinion about what the law achieves

The United Kingdom has enacted legislation under which communicating tax-planning advice can constitute a criminal offence—even where the adviser acts honestly, does not know that the advice falls within the prohibition and has never been told by a court that the underlying analysis is wrong.

That is the effect of Part 6, Chapter 1 of the Finance Act 2026.

The legislation is presented as a prohibition upon the promotion of tax-avoidance arrangements. Its practical reach is considerably wider. “Promotion” includes communicating information with a view to encouraging another person to implement arrangements, making arrangements available for implementation, organising or managing any aspect of them, or arranging for somebody else to undertake those activities.

This is not merely legislation against fraud, sham transactions or dishonest misrepresentation. It criminalises conduct by reference to a later evaluative judgment about the legal effectiveness of the arrangements being discussed.

The primary prohibition

Section 159 prohibits the promotion of arrangements which are marketed, or likely to be marketed, as producing a particular tax advantage where there is “no realistic prospect” that they will produce it.

The provision also permits HMRC Commissioners to prescribe further categories of arrangement by regulations. That secondary route uses a lower threshold: the arrangements must be unlikely to produce the advantage and likely to cause harm to participants.

Parliament therefore created two distinct standards:

• “no realistic prospect”, applicable under the primary statutory prohibition; and
• “unlikely to result”, applicable to categories subsequently prescribed by regulation.

That distinction is important. HMRC cannot convert a disagreement about tax law—or even its opinion that an arrangement will probably fail—into proof that the arrangement had no realistic prospect of working.

Tax law frequently admits more than one professionally defensible interpretation. HMRC loses cases. Decisions are reversed on appeal. Courts disagree with one another. Legislation is amended precisely because its former language produced consequences the Government did not intend.

Against that background, the existence of a “realistic prospect” is not determined merely by HMRC asserting that its preferred construction is correct.

What counts as promotion?

Section 160 gives “promotion” an unusually wide meaning. A person may promote arrangements by:

• communicating information with a view to encouraging their implementation;
• making them available for implementation;
• organising or managing any aspect of them; or
• arranging, directly or indirectly, for another person to undertake those activities.

The definition is not confined to conventional scheme promoters selling standardised products. It is capable of reaching advisers, introducers, consultants, publishers and others who communicate or facilitate tax-planning ideas.

The business or monetary-gain criterion

Section 160(1) does contain an important threshold. The listed activity amounts to promotion only where it is undertaken “in the course of a business or with a view to monetary gain”.

Those are alternative conditions. The prosecution does not have to prove both. Activity undertaken in the course of a business may fall within the definition even if the person receives no separate implementation fee, commission or profit from the particular arrangements. Conversely, activity undertaken outside an established business may still be caught if it is done with a view to monetary gain.

The words “with a view to” focus upon purpose rather than outcome. On the ordinary meaning of the language, the anticipated gain need not ultimately be received. Nor does the subsection say that the gain must be paid directly by the person who implements the arrangements. Introducer fees, contingent remuneration or an indirect financial benefit may therefore be capable of satisfying the condition.

The threshold nevertheless matters. A purely private, gratuitous or academic communication made neither in the course of a business nor with any view to monetary gain does not fall within the statutory definition of promotion. The Act does not criminalise every discussion of a tax-planning proposition.

But that limitation offers relatively little protection to practising tax professionals. Advice supplied as part of an accountancy, consultancy or advisory business satisfies the business limb whether or not the adviser charges specifically for the disputed proposition. The statutory language consequently reaches territory ordinarily occupied by professional advice.

Legally privileged advice is excluded

Section 160(2)(b) provides an express exclusion: a person does not promote arrangements merely by providing legally privileged advice or information. Section 160(3) defines that expression by asking whether a claim to legal professional privilege—or, in Scotland, the corresponding confidentiality of communications between client and professional legal adviser—could be maintained in legal proceedings.

Accordingly, genuine advice or information protected by legal professional privilege is outside the definition of promotion. A lawyer does not commit the promotion offence merely by giving a client privileged legal advice about the effectiveness or tax consequences of arrangements.

That protection is important—but it also reveals the breadth of the underlying prohibition. Parliament considered it necessary expressly to remove privileged legal advice from conduct that would otherwise be capable of constituting promotion.

The exclusion attaches to the privileged character of the communication, not simply to the professional title of the person giving it. The same protection does not extend to tax advice merely because it is professional, careful or given in good faith. Advice given by an accountant, tax consultant or other non-lawyer does not acquire legal professional privilege simply because it concerns the interpretation of tax law.

Nor is section 160(2)(b) a complete immunity for lawyers. Its language is that a person does not promote arrangements “merely” by providing privileged advice or information. Separate conduct involving marketing, making arrangements available, implementation, organisation or management must still be analysed independently; and a communication which is not privileged does not fall within this particular exclusion merely because its author is a lawyer.

A criminal offence without guilty knowledge

Section 163 makes breach of the prohibition a criminal offence.

The extraordinary feature is found in section 159(5): it does not matter whether the person knows, or has reason to believe, that the arrangements fall within the prohibition.

The prosecution is therefore not required to prove that the adviser:

• knew the arrangements had no realistic prospect of success;
• intended to promote ineffective arrangements;
• was reckless about their effectiveness;
• acted dishonestly;
• intended to deceive the client; or
• intended to cause a loss of tax.

The offence is punishable by imprisonment for up to two years.

Alongside criminal liability, the legislation permits a civil penalty of up to £1 million, with an additional amount of up to £5,000 for every person who entered into the arrangements.

The Association of Taxation Technicians warned Parliament that this amounted to strict-liability criminalisation without a defence based upon reasonable professional judgment. It identified the obvious danger: an adviser acting honestly and professionally could be exposed because HMRC, a tribunal or a court later took a different view of a difficult legal question. Those objections did not prevent enactment. The ATT’s evidence to Parliament

Intention is not statutory protection

During the Bill’s passage, the Government repeatedly said that the legislation was not intended to target legitimate advisers who operate to high professional standards and make genuine mistakes.

But ministerial intention is not a statutory defence.

The Act does not say that an honest mistake is exempt. It does not require deliberate or reckless conduct. It does not provide a defence of reasonable care. It does not protect an adviser merely because the opinion was supported by counsel, professional literature, existing practice or a reasonable interpretation of the authorities.

The Government’s assurance therefore sits uneasily beside the legislation Parliament enacted.

If legitimate advisers were not intended to be exposed, the natural solution was to say so in the statute. Parliament could have required knowledge, dishonesty or recklessness. It could have enacted a reasonable-care defence. It did none of those things.

The Government instead left the boundary to prosecutorial discretion and future guidance. That is an inadequate safeguard where the consequence is criminal liability.

Tax planning is not tax evasion

There is a basic constitutional distinction between tax evasion and tax planning.

Tax evasion depends upon dishonesty or deliberate illegality. Criminal punishment is directed at what the defendant knew and intended.

Tax planning asks what legal consequences follow from transactions which are actually undertaken. The answer depends upon legislation, legal rights, judicial authority and the facts. The taxpayer is entitled to arrange affairs according to law, while Parliament remains entitled to change that law prospectively.

Part 6 blurs that distinction. It attaches criminal liability to the communication and facilitation of arrangements based upon an objective, contestable and potentially retrospective assessment of their prospects.

That is not equivalent to punishing a person who fabricates documents, conceals income or knowingly lies to HMRC. It makes the adviser’s liberty depend upon the eventual legal characterisation of advice which may have been honestly given.

“No realistic prospect” must mean what it says

If the provision is to operate compatibly with the rule of law, “no realistic prospect” must be treated as an exacting threshold.

It cannot mean:

• HMRC disagrees with the advice;
• HMRC considers the arrangements artificial;
• HMRC thinks they are more likely than not to fail;
• the law is uncertain;
• the advice advances a novel argument; or
• a court eventually rejects the argument.

A prospect may be realistic without being probable. An argument may ultimately fail without always having been hopeless.

The distinction is confirmed by Parliament’s use of the separate and deliberately weaker expression “unlikely to result” in section 159(2). Treating “no realistic prospect” as equivalent to “probably unsuccessful” would collapse two statutory tests into one.

The prosecution must prove the criminal offence beyond reasonable doubt. Where respectable legal reasoning, relevant authority or genuine professional disagreement establishes a realistic prospect of obtaining the stated tax treatment, the primary prohibition is not engaged.

The chilling effect is the point

The legislation will inevitably deter advice before any prosecution occurs.

An adviser confronting an uncertain question must now consider not merely whether the analysis is professionally defensible, but whether HMRC might later characterise it as having had no realistic prospect of success—and whether explaining it to a client could expose the adviser to imprisonment.

Large institutions may respond by restricting advice to orthodox positions already accepted by HMRC. Smaller advisers may leave the field altogether. Taxpayers without access to privileged legal advice will be affected most severely.

The result is an asymmetry in access to law. Advice from a qualified lawyer may receive the benefit of the privilege exclusion. Functionally similar advice from another tax professional may not.

The legislation therefore risks protecting access to tax-planning advice for those able to obtain specialist legal representation while chilling it for everyone else.

A boundary has been crossed

Part 6 is not simply another penalty aimed at dishonest tax-scheme operators. It establishes a criminal prohibition whose application can depend upon an official or judicial assessment of whether a communicated legal proposition had a realistic prospect of succeeding.

It does so without requiring guilty knowledge and without creating a general defence for honest, careful or reasonable professional advice.

That is the constitutional problem.

A state may punish fraud. It may punish deliberate assistance in tax evasion. It may regulate professional conduct and impose proportionate civil consequences for carelessness. What it should not do is threaten imprisonment merely because a person communicated an honestly held interpretation of tax law which the state later characterises as untenable.

Yet that is the territory into which the United Kingdom has now legislated.

Part 6 of the Finance Act 2026 therefore demands the narrowest possible construction, exacting prosecutorial restraint and early judicial scrutiny. Otherwise, the United Kingdom will have moved from legislating what tax is payable to criminalising the expression of an opinion about what its own tax legislation means.