Some good tips here from the ICAEW for businesses which are under enquiry by HM Revenue and Customs.  Personally, in the last 12 months, I have seen more of my clients' corporate tax, PAYE/NI and VAT affairs being investigated at random by HMRC.  Our clients benefit from our tax investigation service, so we are always in a position to help them with dealing with HMRC investigations of this type, with the cost of our fees covered under the service.