Overview

• HMRC issued a one-week warning on X urging first-time Self Assessment taxpayers to register by Sunday 5 October 2025.
• Paper tax returns for 2024/25 must reach HMRC by 11:59pm on 31 October, with an automatic £100 late-filing penalty even if no tax is due.
• People who may need to register include self-employed earners over £1,000, business partners, those liable for Capital Gains Tax, and anyone with untaxed income such as rent, tips, savings interest, dividends or foreign income.
• Late-filing penalties escalate from the initial £100 to daily £10 charges after three months (up to £900), plus further penalties at six and 12 months, and a ‘failure to notify’ charge can apply, though it may be nil if all tax is paid by 31 January.
• From April 2026, Making Tax Digital will require five submissions a year with a points-based system imposing a £200 fine after four points, and late-payment penalties starting after 15 days with charges rising at 30 days.