An item from the Chartered Institute of Taxation's (CIOT) website provides a link to HMRC's guidance on dealing with tax agents.
The CIOT says:
"Many members will be aware of the Lunn case ( EWHC 240 (Admin)). One point that emerged from that case was that there was a document used by HMRC to govern how it treated agents whose behaviour fell well short of what they had a right to expect. The note referred to as a ‘confidential note’ in the Lunn judgement was in fact simply unpublished internal HMRC guidance to staff.
The professional bodies and HMRC have been in regular dialogue over various aspects of this subject in recent years (members will likewise be well aware of the discussions over ‘Deliberate Wrongdoing by Agents’) and have agreed with HMRC that it would be appropriate to publish this guidance to HMRC staff on the handling of poor behaviour by agents. For the present a version of the note is now attached for members. The guidance will be published by HMRC in due course as part of the regular update of HMRC's guidance to staff.
We intend to discuss with HMRC various issues arising from this guidance."