Incorrectly issued / posted late filing penalty notices

22 Apr 2021

Please see the following message shared on behalf of HMRC. This issue was originally reported on the HMRC Agent Forum as ‘Others-10596’.

'Dear Agents,

We sincerely apologise for the recent security breach and recognise that this is not in line with our Charter standards. We take all aspects of protecting data very seriously so there has been a lot of activity to understand this incident and mitigate future risks. We have received the following report on what happened and what action has been taken as a result:

Background & Recap

We became aware of an issue with SA326D Penalty Notices 23rd March.

We identified that this was down to a software problem with the underlying cause of this issue linked to testing. The issue is limited only to SA326Ds bulk run.

What do we understand now about impacts?

We know that the majority of agents received the correct information and following extraction of data from the affected files we believe the total affected number to be just above 32k.

  • the total number of taxpayers impacted is 32,075
  • 18,496 UTRs/taxpayers notices went to the wrong agent
  • 13,579 UTRs/Taxpayers went to the correct agent
  • 15,459 agents received incorrect envelopes (getting a wrong letter or they don’t know that their letter went to another agent)
  • two taxpayers have received a copy that contains 5 Agent copies in total for other taxpayers

We re-issued the copy notices to agents.


We have issued guidance to Personal Tax Operations and Agent Helpline colleagues
We have posted updates to Agent Forum and informed Accounting Web


We have been assured following the data interrogation carried out by IT colleagues that the total number of incorrect notices sent to Agents is just over 18k.

We are holding an after-action review to understand what went wrong and how we can make sure it doesn’t happen again.'

Any notices that have not already been securely destroyed should be returned to:

Central Mail Unit
Benton Park View
NE98 1ZZ'