This part of GOV.UK is being rebuilt – find out what beta means

HMRC internal manual

Enquiry Manual

Concluding the enquiry: Tax Credits: Reporting your findings to Benefits and Credits

Any uplift in profits as a result of your enquiry may have any impact on the amount of any tax credits or benefits the taxpayer is entitled to claim.

Where Benefits and Credits are a relevant factor, see EM2150 which explains when and how to make a report to Benefits and Credits.