Most HMRC letters are routine. This one is not. Code of Practice 9 is issued when HMRC suspects deliberate tax fraud. It is the most serious of the civil investigation procedures, it comes with a 60 day clock attached, and the decision it asks you to make is one of the few in the tax system that is genuinely difficult to undo. This guide explains what the letter is offering, what the deadline means, and what happens on each of the roads out of it. It is general information rather than advice on your own circumstances, and the wider shape of HMRC investigations is covered in our [complete guide to HMRC investigations](/blog/hmrc-investigation-guide).
What COP9 actually is
COP9 is the code of practice HMRC follows when it suspects deliberate tax fraud and decides to deal with it civilly rather than by prosecution.
Alongside the code, HMRC makes an offer: the Contractual Disclosure Facility. In plain terms, it is a contract. You tell HMRC about the deliberate conduct, in full, and HMRC agrees not to criminally investigate you with a view to prosecution for the behaviour you have told them about.
Two words in that sentence carry the weight. Deliberate, because COP9 is not about an error or a careless mistake, it is about conduct HMRC believes was intentional. And told them about, because the protection covers what you disclose and does not extend beyond it.
The 60 days
You have 60 calendar days to decide whether to accept HMRC's offer of the Contractual Disclosure Facility.
Within that same 60 days, if you accept, you must submit an Outline Disclosure, giving as much detail as you can about the deliberate conduct. The full picture comes later, in a comprehensive disclosure report, but the outline is what has to land inside the window.
Extensions exist only in exceptional circumstances, and they have to be requested. The working assumption should be that 60 days is 60 days.
That is a short period for what it is asking. Gathering several years of records, understanding what actually happened across them, and setting out deliberate conduct accurately is not a weekend's work, which is why the single most useful thing anyone can do on receiving a COP9 letter is start immediately rather than read it twice and put it down.
What accepting involves
Accepting is not simply signing and waiting.
The contract requires full cooperation, a complete disclosure of the deliberate behaviour, and payment of the tax, duties, interest and penalties that are owed. In exchange, HMRC agrees not to pursue a criminal investigation with a view to prosecuting you for the deliberate behaviour you have disclosed.
The protection is real, and it is also bounded. It covers what you tell them. A disclosure that is partial, or that holds something back, does not buy protection for the part that was held back, and an incomplete disclosure inside a CDF is a worse position than it sounds, because you have now signed something saying it was complete.
What rejecting involves
If you reject the offer, HMRC may begin a criminal investigation into your tax affairs at any time.
There is a second consequence that is less widely understood and worth stating plainly. The letter you have signed to reject the offer can be used in court as evidence to show that you intended to deliberately mislead HMRC. A rejection is not a neutral act. It is a document, and it can end up in front of a court.
Rejecting is sometimes the right answer. If there has been no deliberate conduct, then denying it is not only legitimate, it is the truthful position, and people do receive COP9 letters where HMRC's suspicion is wrong. But it is a decision to make with advice and with the records in front of you, not one to make from instinct or indignation.
What happens if you do nothing
Failing to respond within the 60 days is treated as non-cooperation.
HMRC then proceeds on its own terms, by civil or criminal investigation, and the opportunity the CDF represented has gone. Of the three possible responses, this is the only one with nothing to recommend it, and it is also the most common, because the letter is frightening and doing nothing feels like not making things worse.
It does make things worse.
Why this reaches taxi and private hire more than most
HMRC investigation activity targets self-employed workers in cash-heavy industries disproportionately, and the trade sits squarely in that category.
There is also a data picture that did not exist a few years ago. Licensing records, platform earnings that HMRC can access directly, and tax check requirements at licence renewal mean the gap between what is declared and what is visible has narrowed considerably. Most of what that produces is routine: a compliance check, a letter, a request for records. Occasionally it produces a COP9.
Where the trade is genuinely different is that the licence sits alongside the tax position. An investigation that concludes with a finding of deliberate conduct does not stay in the tax world, because it goes to the fit and proper person question too. Our guide to the fit and proper person test covers that side of it.
Getting help with a COP9 letter
COP9 is the point at which doing it yourself stops being sensible. The decision is time limited, the disclosure has to be accurate and complete, and the consequences of getting either part wrong run to prosecution.
Our HMRC investigations work covers COP9 and the Contractual Disclosure Facility, and our penalty defence work covers what follows on the civil side. If a COP9 letter has arrived, note the date on it, count the days, and get in touch early in the window rather than late in it.