the common misconception is that HMRC will go back 6+1 but the reality is that if in doing that they encounter evidence of actual fraud rather than error then they can go back right to inception of the business.
There was a discussion about this in one of the advanced audit lectures over on opentuition (can't remember whch one and I don't fancy sitting through 20+ hours of lectures to find it) where it was being discussed at what period was it safe for a business to dispose of old records and the answer is basically never although some firms at the lectures were saying that their policy was 15 years.
Thats at odds with the 6+1 rule which seems to be bounced around the industry.
Now, whilst that answers the direct question the other thing to consider is materialarity and whether its worth HMRC pursueing the case as there are costs involved in such. In some cases such as IR35 ones where they are attempting to form a precedent they will pursue the perceived liability regardless of the cost. In others they "may" make the call that its not worth their time to pursue.
Most cases beyond 7 years are not pursued as the yield is unlikely justify the cost. Thats not saying that they cannot go back more than 7.
I've not touched on the potential money laundering issues as your message was too brief to understand the full scope of the actual question (and the question answered may not be what you were intending to ask).
kind regards,
Shaun.
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Shaun
Responses are not meant as a substitute for professional advice. Answers are intended as outline only the advice of a qualified professional with access to all relevant information should be sought before acting on any response given.