The UK Parliament’s Treasury Committee published a letter to HM Revenue and Customs (HMRC) warning that HMRC’s failure to report details of a breach affecting around 100,000 taxpayers was “unacceptable”. The breach only became apparent to the Committee when a notification was published on HMRC’s website on the same day as a live session, and it involved an estimated cost to taxpayers of around GBP 47 million. During the session, HMRC witnesses told the Committee the department had worked with agent and representative bodies on the incident. The Committee also published a letter from the Association of Chartered Certified Accountants stating it had not discussed the phishing incident with HMRC and was not aware of it prior to the Committee’s hearing on 4 June.