If HMRC are to undertake a code of practice 9 investigation they suspect serious fraud but are seeking to collect tax, interest and penalties through civil settlement. However the seriousness of your position should not be underestimated and you should not deal with such an investigation without the assistance of a professional advisor.
If you are notified you are under criminal investigation by HMRC you should immediately seek professional advice. HMRC have many of the powers of the police and certain officers have the power of arrest and also the right to execute warrants.
HMRC often execute warrants in the early morning known as “dawn raids” and these usually involve a number of individuals and premises. Such raids are extremely intimidating and disorientating but it is important that you seek advice as soon as possible. Remember that under the warrant your phone, computer etc. may be taken so ensure that you keep contact details available. This is important as under judicial review in a number of cases HMRC have been found to have acted outside their powers in executing a warrant.