What is a Code of Practice 8 investigation?
Answered 17 March 2026
HMRC Guidance / Practice
A Code of Practice 8 (COP 8) investigation is a formal civil investigation conducted by HMRC's Fraud Investigation Service (FIS) technical teams. Here is what the guidance says about it:
What it is and when it applies
COP 8 applies to all investigations worked by FIS technical teams where the Contractual Disclosure Facility (CDF) / Code of Practice 9 is not appropriate. In other words, it covers cases that warrant investigation by HMRC's specialist investigators (for example, because a substantial amount of tax is at risk) but where serious fraud is not suspected — and therefore the CDF procedure has not been invoked.
Primary use cases
COP 8 is primarily used to investigate cases of tax avoidance. However, it can also be used where FIS wishes to investigate a case involving evasion but the criteria for using COP 9 under the CDF procedure do not apply.
Penalties
Cases investigated under COP 8 will often attract a liability to penalties.
How it works in practice
- A copy of the Code of Practice 8 leaflet must be issued to the taxpayer (and their adviser) at the start of the investigation.
- The investigation typically begins with an initial meeting, the main purpose of which is to establish the facts of the particular taxation issue(s) that justified registration.
- Where a Self Assessment return is under enquiry, the opening meeting notice will normally incorporate the written notice of enquiry under s.9A(1) TMA 1970.
Distinction from COP 9
The key distinction is that COP 9 is reserved for cases where serious fraud is suspected, and involves the Civil Disclosure of Fraud (CDF) procedure, which gives the taxpayer the opportunity to make a complete disclosure or face potential criminal prosecution. COP 8 does not involve the CDF procedure — there should be no occasion when the CDF procedure is applied in a COP 8 case.
Movement between Codes
While a COP 8 case can be re-designated to COP 9 if new information arises during the investigation (e.g. evidence of serious fraud emerges), COP 9 cases should never be re-designated to COP 8.
Citation sources
SI Technical Teams operate under two published Codes of Practice. Code of Practice 9 covers cases worked under the Civil Disclosure of Fraud (CDF) procedures, i.e. where serious fraud is suspected. Code of Practice 8 covers cases which warrant investigation by SI (because, perhaps, a substantial amount of tax is at risk) but where the CDF procedure has not been invoked. Before you register an investigation you must decide which Code of Practice (either 8 or 9) is appropriate. That code must b
The HMRC Investigation of Fraud Statement The Commissioners of HMRC reserve complete discretion to pursue a Criminal investigation with a view to prosecution where they consider it necessary and appropriate. In cases where a criminal investigation is not commenced, the Commissioners may decide to investigate using the Code of Practice 9 investigation of fraud procedure. Under the investigation of fraud procedure, the recipient of Code of Practice 9 is given the opportunity to make a complete and
The main purpose of an initial meeting in a FIS Code 8 case is to establish the facts of the particular taxation issue(s) that justified registration as an Investigation. The initial notification of FIS interest in a case is likely to be by means of correspondence. An earlier contact may have been made by telephone but a letter should always confirm this. The Investigator should make it clear that the investigation is to be undertaken by FIS and that Code of Practice 8 will be followed. A copy o
Review cases are not allocated to a specific Code of Practice. This is because it is part of the review process itself to decide under what Code of Practice a case is to be worked if the risks are to be registered for investigation. A decision on what Code an investigation case is to be opened under does not inevitably determine the Code that will apply to the case during its lifetime in SI. As investigation cases develop circumstances can arise where the case needs to be moved from one Code to
COP 8 applies to all investigations worked by Fraud Investigation Service (FIS) technical teams where the Contractual Disclosure Facility (CDF) COP 9 is not appropriate. COP 8 is primarily used to investigate cases of avoidance, however there will occasionally be circumstances where FIS wish to investigate a case involving evasion but for various reasons the criteria for using COP 9 under the CDF procedure do not apply. In these circumstances COP 8 will be used instead. Cases investigated using