GOV.UK
Closing the enquiry: issuing the penalty leaflet: telephone calls
If you become aware of the possibility of penalties during a telephone conversation you should bring the conversation to an end and then write to the customer(s) setting out the position and including the text shown at CCM14230 above.
This will typically happen where you have issued your opening letter and the customer telephones you to discuss it or you have asked for some further information. Where the customer has admitted an error for which a penalty is likely to be considered you must make them aware of their rights and issue the penalty leaflet Tax credits - Penalty decisions.
Where the telephone call is being handled by an AO the papers must be passed to a Band O to issue the letter and conclude the settlement.