Supervised alpha — demo available
Draft tax packages your reviewers control, down to the penny.
The Accountancy Brain is a reviewer-assistance application for UK accountancy practices. It prepares controlled, reviewer-gated draft packages — Self Assessment, VAT, payroll, P11D and micro-entity CT — from deterministic arithmetic over versioned HMRC facts. It is a tool for qualified accountants, not a self-serve product for taxpayers.
Every package requires qualified-accountant review, authorisation, and external submission. The application does not transmit to HMRC, Companies House, or any government system.
- automated tests
- 8,500+
- release gates passing
- 11/11
- adversarial audit waves, hand-checked to the penny
- 5
- transmissions to HMRC — by design
- 0
How it works
A controlled pipeline from intake to deliverable pack
A browser-based, local-only operator UI walks each engagement through a fixed sequence. Nothing skips ahead of its evidence, and nothing leaves the practice without a reviewer's signature.
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Login and client intake
Structured intake captures the engagement scope and client facts up front.
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Evidence collection
Source documents are attached to the engagement — the figures that follow are traceable back to them.
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Bank ingestion
Bank data is ingested and staged for categorisation.
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Resolution queue
Ambiguous items land in a queue for a human decision. The system does not guess past them.
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Prepare
The deterministic engine computes the draft package from versioned HMRC facts — Decimal arithmetic, not an LLM estimating numbers.
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Workpaper
Every figure carries provenance: where it came from and which rule produced it.
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Reviewer sign-off human gate
A qualified accountant reviews and signs off. The sign-off is hash-bound to the exact package reviewed — change a figure and the signature no longer applies.
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Deliverable pack
The authorised draft is assembled into a deliverable pack for the practice.
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Transcription pack
A transcription pack supports external submission by the accountant. The application itself transmits nothing to HMRC or Companies House.
A scoped client portal handles intake and document upload only — clients never touch the preparation pipeline.
Coverage
The schedules a small practice actually files
Current coverage in supervised alpha. Cases outside these boundaries are hard-blocked — the application refuses rather than guesses.
Sole traders SA103
Self-employment schedules within Self Assessment.
Landlords SA105
Property income, including multi-property portfolios.
Capital gains SA108
CGT computations within Self Assessment.
Partnerships SA104
Partnership pages for individual partners.
Foreign income SA106
Foreign income pages within Self Assessment.
Scottish residency
Scottish rates and bands applied where residency requires them.
Marriage allowance & CIS
Marriage allowance transfers and Construction Industry Scheme deductions.
Owner-manager Ltd packs
Draft packages for owner-managed limited companies.
VAT standard accrual
Standard-accrual VAT, including domestic reverse charge (audited).
Payroll monthly
Monthly payroll runs with audited NIC arithmetic.
Benefits P11D
P11D benefit-in-kind computations.
Micro-entity CT FRS 105
Micro-entity corporation tax draft accounts.
Anything not on this list is out of scope today, and the application will say so explicitly rather than produce a package it cannot stand behind.
Why an accountant can trust it
Deterministic where it counts, human where it matters
The engine is built to be checked, not believed. Every design decision assumes a sceptical reviewer will want to see the working.
Deterministic Decimal arithmetic
Computations run on exact Decimal arithmetic from versioned HMRC facts (data/tax/*.json) — not an LLM guessing numbers. Same inputs, same output, every time.
8,500+ tests, 11/11 release gates
Over 8,500 automated tests and 11/11 release gates stand between a change and a release.
Audited to the penny
Adversarially hand-audited across five waves: income tax, NIC, CGT, CT, VAT including domestic reverse charge, P11D and payroll.
Evidence gating
A mismatched P60 or CIS statement blocks the package from progressing. Evidence has to reconcile before a draft can move forward.
Hash-bound sign-off
Reviewer sign-off is cryptographically bound to the exact package reviewed. If anything changes afterwards, the signature no longer applies.
Refuses rather than guesses
Unsupported cases hit a hard block. The application declines work outside its audited coverage instead of producing a plausible-looking wrong answer.
Full audit trail & figure provenance
Every workpaper shows where each figure came from, and a complete audit trail records every action on the engagement.
GDPR export and delete
Built-in export and delete verbs support the practice's data-protection obligations for every client record.
Honest status
Where this product actually is
This page avoids the usual launch theatre. Here is the current state, plainly.
Supervised alpha
The Accountancy Brain is in supervised alpha. A working demo is available today, and every engagement in the product runs under qualified-accountant supervision.
There are no customer testimonials on this page because we are not going to invent any. If you want evidence, book the walkthrough and inspect the workpapers yourself.
- It does prepare reviewer-gated draft packages with full figure provenance.
- It does block packages whose evidence does not reconcile.
- It does refuse cases outside its audited coverage.
- It does not file, submit, or transmit anything to HMRC, Companies House, or any government system.
- It does not serve taxpayers directly — it is a tool for qualified accountants.
- It does not replace the accountant's professional judgement or responsibility.
Every package requires qualified-accountant review, authorisation, and external submission. The application does not transmit to HMRC, Companies House, or any government system.
Indicative pricing
Pricing hypotheses, stated as such
These prepared-package tiers are working hypotheses we are testing with early practices — not a published price list.
Sole trader package
£450
indicative, per prepared package
Landlord package
£600
indicative, per prepared package
Small Ltd package
£1,300
indicative, per prepared package
All figures are indicative and subject to change during supervised alpha. Talk to us about what a pilot would look like for your practice.
Next step
See the workpapers for yourself
A demo is available now. We will walk you through a real engagement end to end — intake, evidence, resolution queue, workpaper, sign-off — and you can interrogate any figure's provenance.
Or email ben@revivmedia.com directly.