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MTD - HMRC Compliant Module · How-to guide

Connect a taxpayer to HMRC

Follow this guide to start the taxpayer OAuth journey from a profile and return to Britixo with a tenant-bound HMRC connection. The guide then takes you through the correct route, the checks to complete before making changes, the workflow in order, and the evidence to review afterwards.

Audience: Administrators, taxpayers, accountants and authorised agentsModule v1.0.0Code-backed
Jump to steps
Where to goTax Centre → Settings → Profiles & HMRC authority
Before you startRequired access: Manage HMRC connection permission plus the relevant taxpayer/agent authority. Work on the correct tenant and taxpayer profile. Reconcile the underlying Accounting & Bookkeeping records before relying on prepared tax totals.

What you’ll accomplish

Start the taxpayer OAuth journey from a profile and return to Britixo with a tenant-bound HMRC connection. The MTD module stores tax profiles, HMRC authority, obligations, frozen filing snapshots, approvals and audit evidence, while Accounting remains the primary financial record system.

Follow these steps

  1. Go to Tax Centre → Settings and find the required taxpayer profile.
  2. Select Connect taxpayer.
  3. Britixo creates a short-lived OAuth state and redirects the browser to the configured HMRC authorisation endpoint.
  4. The taxpayer signs in directly with HMRC and grants the requested software authority; do not enter Government Gateway credentials into Britixo.
  5. HMRC returns the browser to the registered callback route.
  6. Britixo exchanges the authorisation code server-side, encrypts the token material and binds the connection to the current tenant/profile.
  7. Return to the Tax Centre and run the relevant VAT or Income Tax sync to verify the connection.

Checks before you continue

Taxpayer profileAlways verify the correct profile, tax regime and masked identifiers before preparing or submitting.
Tenant contextTax records, HMRC authority and audit history must stay inside the current Britixo tenant/runtime.
Accounting sourceSource tax figures must come through the verified Accounting digital-link adapter with transaction lineage.
Approval stateThe exact frozen snapshot must carry the approvals required by its filing mode before HMRC submission.

Technical basis for this guidance

This guide was checked against controllers/Mtd_hmrc_oauth.php; libraries/Mtd_hmrc_oauth_service.php; libraries/Mtd_hmrc_crypto.php; libraries/Mtd_hmrc_fraud_header_service.php. The user instructions describe only behaviour exposed or enforced by the supplied module. Internal secrets, encrypted token values and database identifiers are intentionally not shown to ordinary users.

Compliance and operational boundaries

  • Britixo Accounting & Bookkeeping remains the authoritative ledger; the MTD module is a tax preparation/submission layer.
  • Government Gateway usernames and passwords must never be entered into or stored by Britixo.
  • A tax filing must not proceed when transaction-level digital lineage cannot be proven.
Accounting interlinkFor transaction creation, tax mappings, banking, reconciliation, journals, reports and source-document corrections, use the Accounting & Bookkeeping Help Centre. Correct the bookkeeping source first; do not type replacement totals into MTD merely to clear an error.
Accounting & BookkeepingOpen related guidanceAll MTD - HMRC Compliant guidesOpen related guidance