Overview

• Taxpayers must tell HMRC about changes to names or addresses, income, relationship or family status, and gender.
• Employers and pension providers report job starts, finishes, and pay changes, but individuals must report other income such as rent, taxable benefits, company benefits, and capital gains.
• Failure to notify can lead to incorrect tax, with deliberate concealment risking penalties that can double the unpaid amount.
• HMRC categorises failures as non‑deliberate (0%–30%), deliberate but not concealed (20%–70%), or deliberate and concealed (30%–100%), and it may waive penalties for a reasonable excuse.
• Notifications can trigger tax‑code changes, a Self Assessment requirement, or refunds; legal gender changes are usually passed to HMRC automatically, which then updates records, informs DWP, restricts access, and moves cases to Public Department 1.