You Missed the Self Assessment Deadline. Now What?

Late filing and late payment are separate

These are two distinct penalty regimes and you can be caught by one and not the other. Filing on time but paying late attracts interest and payment penalties. Filing late attracts a filing penalty even if you owe nothing at all.

That last point surprises people: a nil return filed late can still carry a penalty.

If you cannot pay, file anyway. Filing is free and stops the filing penalty clock. Paying is a separate problem with its own, more flexible, solutions.

It escalates

Filing penalties start with a fixed amount and increase the longer the return is outstanding, with further charges at set intervals and daily penalties in some circumstances. The specifics have changed over time and differ between regimes, so check the current position on GOV.UK rather than working from an old figure.

The escalation is the argument for acting today rather than when you feel ready.

Time to Pay

If the return is filed and you cannot pay, HMRC can agree an instalment arrangement. Agreeing one before the payment due date generally avoids late-payment penalties, though interest continues to run on the outstanding balance.

Arrangements are more readily agreed for someone who has filed and made contact than for someone who has gone quiet. Filing first genuinely improves your position.

Reasonable excuse

Penalties can be appealed where there is a reasonable excuse, which generally means something unexpected and outside your control that stopped you filing. Serious illness and bereavement are recognised; forgetting and being busy are not.

If you have a genuine excuse, appeal rather than accepting the penalty, but be realistic about what qualifies.