Self-Assessment Late Filing Penalty

The self-assessment filing deadline is 31 October for paper returns and 31 January for online returns. An initial GBP 100 penalty is issued automatically if the return is even one day late. After 3 months, daily penalties of GBP 10 per day begin, up to a maximum of GBP 900 over 90 days. At 6 months, a further penalty of 5 percent of the tax due or GBP 300 (whichever is greater) is charged. At 12 months, another penalty at the same rate applies, though in serious cases HMRC may charge up to 100 percent of the tax due. Filing the return as soon as possible limits the accumulation of penalties. HMRC also charges separate late payment penalties if the tax itself is not paid by 31 January.

Common situations include: missing the 31 January deadline due to illness or personal circumstances, not realising a self-assessment return was required, receiving a penalty notice when the return has already been submitted, receiving escalating penalties while dealing with a complex tax situation, and wanting to appeal a penalty on the grounds of reasonable excuse.

Self-assessment penalties are set out in Schedule 55 of the Finance Act 2009. Paragraph 3 imposes the initial GBP 100 fixed penalty for late filing. Paragraphs 4 and 5 cover the daily penalties and 6-month and 12-month penalties respectively. Section 118(2) of the Taxes Management Act 1970 defines reasonable excuse, though it does not provide an exhaustive list. HMRC's guidance confirms that insufficient funds alone do not constitute a reasonable excuse, but the underlying cause of the shortfall may qualify. Appeals against penalties may be made to HMRC under Section 31A of the Taxes Management Act 1970, and if unsuccessful, to the First-tier Tribunal (Tax Chamber).

People who receive late filing penalties often consider filing the return as quickly as possible to prevent further penalties accumulating, checking whether they have a reasonable excuse that HMRC might accept, appealing the penalty directly to HMRC in the first instance, and if the HMRC appeal is unsuccessful, considering an appeal to the First-tier Tribunal (Tax Chamber). Common reasonable excuses that HMRC may accept include serious illness, bereavement of a close relative, and postal delays. Some people check whether they were actually required to file a self-assessment return at all.

Common mistakes include: assuming the penalty will not apply because no tax is owed (the GBP 100 penalty applies regardless), ignoring penalty notices which causes penalties to escalate significantly, not filing the return even after receiving a penalty (the penalties continue to accumulate), not being aware that late payment penalties are separate from late filing penalties, and assuming that being too busy or forgetting constitutes a reasonable excuse (HMRC generally does not accept this).