Can you explain your tax software’s figures? Build a digital records trail

A proposal worth preparing for

HM Revenue & Customs published its computer-records reform package on 13 July 2026, with a technical consultation deadline of 7 September. The policy proposes clarifying access to digital information, including how tax figures are produced. It specifies Royal Assent to Finance Bill 2026–27 as the intended start point. These are proposals, not new duties established by the publication.

For a finance team, the useful question is practical: could someone follow a figure from its source through the bookkeeping system to the return? The checks below are TaxMirror’s suggested preparation, not a prescribed HMRC checklist.

Map the systems behind one reported figure

Choose one recently reported total and draw its route: original transactions, imported records, ledger accounts, any spreadsheet adjustment, and the final reporting output. Name the system and person responsible at each stage. Note where a bookkeeper, accountant or software provider holds part of the trail.

For each handover, record the period, export date, report settings and filters. A file called final.csv tells a later reviewer little about whether cancelled invoices, credits or a different date range were included. Use a short explanation of the choices that produced the total.

The draft legislation proposes replacing computer-focused language with broader digital-information terms and adding creators or developers to the relevant assistance provision. That makes the distinction between a business’s own records and a provider’s technical explanation useful to understand; it does not settle what any particular notice can demand.

Keep the calculation understandable

As an internal control, save the calculation inputs alongside the output you relied on. Where a spreadsheet changes a ledger total, retain its formulas and a brief reason for the adjustment. Where software applies a rule automatically, note the setting used and where its explanation can be found.

Consider a simple example: a sales report and a return working paper show different totals because one uses invoice dates and the other includes a separate adjustment. A useful trail would show both reports, the date basis, the adjustment and the reconciliation. It would also record any unresolved difference. A balancing entry without an explanation does not help another person reproduce the decision.

Test the trail with a colleague who did not prepare it. Ask them to locate the source, rerun the export and explain the difference between the ledger and the reported figure. Treat missing settings or inaccessible files as actions for the team to resolve.

Check access before changing software

Before ending a subscription or moving to a new platform, check what you can export and reopen. Include attachments, transaction identifiers, adjustments and the reports used for filed periods in your migration plan. Assign responsibility for the archive and test that an authorised colleague can read it.

Ask your provider what historical configuration and calculation explanations remain available after migration. Record the answer and any gaps. These are practical continuity checks; this article does not set a universal retention period or require you to buy an additional service.

Keep the proposal and an actual request separate

HMRC’s policy says section 114 would remain a supporting provision: an existing lawful information power and safeguards would still govern a request. It does not propose a standalone power. ICAEW’s response, published on 8 September 2026, also discusses the package as draft Finance Bill provisions.

If a request arrives, have the person responsible for tax compliance or your adviser check its scope, period, deadline and applicable safeguards. Use the records trail to identify relevant material and gaps. Avoid treating this general preparation exercise as a decision about the validity of a notice or the information you must provide.