Voluntary disclosure is the umbrella term for any situation where a taxpayer comes forward to HMRC and corrects an under-declaration before the agency opens a formal enquiry. The principle is simple — disclose, pay tax plus interest plus a reduced penalty, and move on. The execution is less simple, because HMRC operates several distinct disclosure routes and choosing the wrong one can be expensive. This guide walks through the options as they stand in 2026.
Why voluntary disclosure pays
The penalty regime treats voluntary (unprompted) disclosure significantly more favourably than disclosure made after HMRC has begun an enquiry. For a deliberate inaccuracy:
- Unprompted: minimum penalty of 20% of tax (after maximum mitigation).
- Prompted: minimum penalty of 35% of tax.
For careless inaccuracies the unprompted minimum is 0% — versus 15% for a prompted disclosure. The gap is even wider for offshore matters where penalty multipliers apply. Disclosure also typically protects against criminal investigation in most circumstances and provides certainty about the years and issues covered.
The main facilities
Digital Disclosure Service (DDS)
The general-purpose route for most domestic under-declarations. Suitable for one-off errors, omitted income, incorrect expense claims, and similar situations that do not fit a campaign-specific facility. Access via the GOV.UK portal — you receive a Disclosure Reference Number (DRN), then have 90 days to file the full disclosure and pay.
Worldwide Disclosure Facility (WDF)
The dedicated route for offshore matters — foreign bank interest, foreign rental income, overseas capital gains, non-UK trust distributions, and so on. Operates via the DDS portal but with offshore-specific calculations and penalty multipliers. We covered this facility in depth in our insights library.
Let Property Campaign
For UK landlords (resident and non-resident) with under-declared rental income from UK residential property. Open-ended in time and the most heavily used campaign. We have helped many landlords through this route — typical issues include "I always thought rental income under the personal allowance was tax-free", "we let the property for years through a managing agent who handled the taxes" (when they did not), or "we converted our home to a rental but kept claiming Private Residence Relief".
Code of Practice 9 (COP9) and the Contractual Disclosure Facility
This is the route for taxpayers who suspect HMRC may be investigating them for fraud. Initiating a COP9 disclosure provides immunity from criminal prosecution in exchange for complete and honest disclosure of all tax irregularities (not just the ones HMRC is asking about). The process is rigorous and adversarial in tone — but for serious cases, it is often the only sensible path. COP9 disclosures should never be attempted without specialist representation.
Other campaigns
HMRC has historically run shorter targeted campaigns — e.g. the Plumbers Tax Safe Plan, the Tax Health Plan for medical professionals, the Card Transaction Programme. Most of these have closed, with errors now handled via the DDS. Periodically a new campaign is launched (the most recent being targeted at e-commerce sellers in 2024) and these typically offer a few months of preferential terms.
Choosing the right facility
The choice depends on the nature of the under-declaration:
- Domestic, no fraud suspected: Digital Disclosure Service.
- Anything with an offshore component: Worldwide Disclosure Facility (which sits within the DDS infrastructure).
- UK residential rental: Let Property Campaign.
- Suspected fraud, complex deliberate cases: Code of Practice 9.
You cannot use a non-campaign route to disclose something that falls within a campaign; HMRC will reject and redirect. Conversely, using a campaign route for something it does not cover is also a procedural error.
The disclosure process in detail
- Registration: Submit the initial notification via the GOV.UK portal. You receive a Disclosure Reference Number (DRN).
- 90-day clock starts: You have 90 days to make the full disclosure and pay (or arrange to pay).
- Full disclosure: A detailed submission with all relevant tax years, calculations of tax, interest, and proposed penalty. The supporting workpapers (typically a spreadsheet model) must reconcile to the figures.
- Payment: Tax, interest and penalty paid in full or by an agreed Time to Pay arrangement.
- HMRC review: typically 3 to 6 months for straightforward disclosures, longer for complex offshore cases.
- Contract settlement: A formal written agreement that concludes the matter.
The numbers and lookback periods
The number of years you must include in the disclosure depends on behaviour:
- Innocent error: not strictly applicable — innocent error means no penalty and a 4-year window.
- Careless: 6 years.
- Deliberate: 20 years.
- Offshore matters under FTC: potentially longer.
The right characterisation of behaviour is critical and is one of the areas where specialist advice pays for itself many times over. Under-characterising (saying "careless" when the facts point to "deliberate") risks HMRC rejecting the disclosure and treating it as prompted. Over-characterising costs more years of disclosure than necessary.
What documents do you need?
The disclosure model typically reconstructs the under-declared income or gains across all relevant years. You will need:
- Bank statements (UK and foreign).
- Source documents — rental agreements, invoices, brokerage statements, payslips, exchange records.
- Records of any expenses or reliefs you intend to claim against the income.
- Calculations of foreign currency conversion at relevant rates.
- Self Assessment returns as filed (the baseline against which the corrections are made).
Practical advice
- Do not register prematurely. Registration starts the 90-day clock. Engage specialist help, scope the disclosure, gather the records, then register when you have a credible plan.
- Do not under-state the disclosure. If HMRC discovers additional issues during review, the disclosure can be invalidated.
- Do not delay further once you have decided to disclose. Every month of delay risks HMRC writing to you first, converting your disclosure to prompted.
- Keep the disclosure documentation for at least six years after settlement. Audit and follow-up enquiries can occur.
The economics of voluntary disclosure are almost always favourable. The mechanics are unforgiving. To discuss your situation confidentially, book a 30-minute call with PushDigits, or contact our team via the contact page. We integrate disclosure work with ongoing Self Assessment and tax planning support, so the years after disclosure are clean and the agency's confidence in your future returns is rebuilt. Read more about our broader practice on the about page.