HMRC’s Personal Income Statistics by tax year contain a constituency-level breakdown of taxpayer numbers for the tax year 2020 to 2021. This is the latest outturn data available and can be found in Table 3.15 below: https://assets.publishing.service.gov.uk/media/6402022ad3bf7f25f5948f90/Table_3.15_2021.ods The parliamentary constituency breakdowns published in these statistics are consistent with those used at elections since 2010 and do not contain the new boundaries that will be in place at the next election. Further breakdowns of this information are not routinely published. For projection years, HM Revenue and Customs does not publish this information at constituency level.