HMRC had no general duty to inform a taxpayer whether they were liable to the high-income child benefit charge, and to monitor their income and notify them if they tipped over the adjusted net income threshold. 

The appellant’s partner was in receipt of child benefit. During the tax year 2017/18, the appellant had an adjusted net income of more than £60,000. The appellant was liable to the high-income child benefit charge (HICBC). On 3 March 2022, HM Revenue and Customs (HMRC) sent a notice to file to the appellant for 2017/18. The appellant filed his return on 18 July 2022, in which he included over £60,000 in taxed interest but did not complete the HICBC boxes. On 15 March 2023, HMRC opened an enquiry into this aspect of the appellant’s tax return and on 17 May 2023, issued a closure notice amending his self-assessment return and assessing him to HICBC. The appellant appealed. 

The appellant argued (among other)