Penalties for Inaccuracies: Other Penalty Issues: Double jeopardy
You must check the date from which these rules apply for the tax or duty you are dealing with. See CH81011 for full details.
A person whose conduct makes them liable to a penalty as a result of an inaccuracy or an under-assessment as well as a prosecution for a criminal offence, will not suffer both effects.
If you conduct a compliance check with a view to a criminal prosecution you should not assess any penalty relating to the inaccuracy or understatement.
If, later, it is decided not to prosecute you may then consider penalties.