The Simplification HMRC Cannot Compute

On 10 July 2026, HM Treasury and HMRC published their "Tax update 2026: simplification, modernisation and fairness" — a package of eleven consultations and announcements. The headline measure: from April 2029, hundreds of thousands of Income Tax Self Assessment (ITSA) taxpayers with PAYE income will have their forecast tax liabilities collected in-year through PAYE, rather than settling a lump sum the following January. HMRC's framing is clean and sympathetic. Smaller, regular payments will help reduce tax debt and spare taxpayers the shock of a large, unexpected bill.

This is a appealing story. It is also a story that breaks down the moment you ask a single question: who knows what each of those millions of taxpayers actually needs?

What the Story Claims

The government presents the change as genuine simplification. By aligning the timing of tax payments with the rhythm of employment income, HMRC argues it can reduce the administrative burden on individuals, shrink the existing annual tax-debt accumulation, and modernise a system that, in the words of the announcement, "has not been reformed since 1965" in some areas. The package includes a new zero rate of VAT for land intended for social housing, a review of employer travel-expense flat rates, digitisation of the "option to tax" process for VAT, ISA reform, and an extension of online marketplace liability. Eleven separate reforms, all under the banner of making tax "simpler, more modern, and fairer."

The Austrian Diagnosis

The knowledge problem, first articulated by Friedrich Hayek in his 1945 paper "The Use of Knowledge in Society," states that the economic problem of society is not merely how to allocate given resources, but how to coordinate the dispersed fragments of knowledge that no central authority can possess. Every individual taxpayer holds unique, local, often tacit knowledge: when they plan to change jobs, whether a large one-off expense is coming, whether a business will expand or contract in the next twelve months. HMRC's announcement assumes this knowledge can be captured, aggregated, and acted upon by a central administrator. It cannot.

The proposed PAYE reform does not ask the individual taxpayer what payment cadence suits their cash-flow position. It assigns one. The knowledge problem is compounded by what Ludwig von Mises called the calculation problem: HMRC's "simplification" is an estimate of administrative cost without any underlying exchange at the margin to measure from. The accumulated tax debt is real, but it is the product of a system in which the state has progressively displaced the price mechanism from the timing of tax payments. You cannot calculate your way to a solution when the data you need — the marginal utility of each taxpayer's cash at each point in time — does not exist in any collectable form.

The zero-rate VAT for social housing land is the same pattern at one remove. HMRC proposes to define, from Whitehall, which land is "intended" for social housing and which is not — a classification problem that will generate its own compliance industry, lobby groups, and boundary disputes. The knowledge of what housing is genuinely needed, at what price, in what location, is dispersed across millions of buyers, sellers, builders, and local authorities. The VAT zero rate assumes the state can substitute for all of it.

Hayek and the Calculation Problem

Hayek's central insight was that prices constitute a mechanism for communicating information — and that no bureaucrat, however well-intentioned, can replicate what the price system does automatically. When HMRC announces it will set the payment cadence for millions of taxpayers, it is attempting something akin to replacing the price of copper with a committee decision. The committee can guess. It cannot know.

Frédéric Bastiat would have called the accumulated annual tax debt the seen — the measurable problem that justifies the intervention. The unseen is the productive activity distorted by yet another layer of centrally-determined timing. Taxpayers who might have arranged their affairs to smooth cash flows — taking on a contract, delaying a purchase, accelerating an invoice — will instead find their obligations settled by an HMRC algorithm calibrated to the average. The entrepreneur who structures a business around genuine cash-flow realities will be overridden by a system that cannot see them.

Why This Matters for Sound Money

Sound money requires that the time-structure of an agent's liabilities match the time-structure of their income. This is not an ideological preference — it is a logical requirement of any economy that uses money as a unit of account and a store of value. When the state intervenes to set payment calendars, it distorts this matching. The PAYE reform from 2029 does not create a better match; it replaces the taxpayer's own judgement about timing with the state's.

The "simplification" package is itself evidence of the calculation problem it cannot solve. Eleven separate consultations were required to produce a package that HMRC frames as simplification. A genuinely simpler system would require less central specification, not more. The complexity of the announcement — the carve-outs, the transition periods, the definitions of "legitimate high street businesses" and "social housing land" — is not accidental. It is the natural product of any attempt to administer a tax system from the centre: each intervention generates new edge cases, each edge case generates new guidance, each guidance generates new disputes.

What the Market Is Already Doing

On Ethereum mainnet, programmable settlement rails already do what HMRC’s 2029 PAYE reform proposes to do — but without the central administrator. Value can move continuously, by the second, against a pre-funded balance, with the relevant withholding fraction settled at the moment the income itself arrives. No lump-sum January bill. No HMRC algorithm. The timing matches the actual structure of income because the individual participant chose it.

The contrast with HMRC’s 2029 PAYE reform is exact. The Ethereum settlement layer resolves the same problem — aligning the timing of tax payments with the rhythm of income — without requiring any central authority to specify the cadence. The knowledge problem is resolved because the knowledge sits with the parties who actually have it. Gitcoin Grants, also on Ethereum mainnet, demonstrates a related principle: quadratic funding that aggregates dispersed individual preferences about public goods, without a ministry specifying what counts as simplification.

These are not fringe experiments. Ethereum mainnet has been live, without a central operator, since 30 July 2015, and has carried hundreds of billions of dollars of cumulative settlement across a decade of operation. Its smart-contract layer is open, auditable, and self-executing. It does not require HMRC's annual compliance budget, its consultation apparatus, or its 1965-era systems. It simply assigns the timing problem to the person who holds the relevant knowledge.

Looking Ahead

The PAYE reform will not take effect until April 2029. That is three years of consultation, implementation, and compliance guidance before the first taxpayer is collected under the new system. By then, the knowledge problem will have done its work: the cash-flow distortions generated by the reform will have accumulated, the boundary disputes will have spawned their own case law, and HMRC will publish another "simplification" package. The promise of simplification is structurally immune from delivery. Not because the civil servants are incompetent, but because the task they have set themselves — knowing, from the centre, what every taxpayer needs — is impossible by definition.

The alternative is already running on Ethereum. It is quieter, faster, and cheaper. And it does not require a consultation.