If your return is late and you get charged a late filing penalty is there anything you can do? You can try to appeal and hope that you have a reasonable excuse that HMRC will accept.

HMRC has previously published lists of some of the unsuccessful attempts, including excuses like the death of a goldfish, a run-in with a cow and a hamster eating the post.

You need to show that you have taken reasonable care in trying to meet your obligations. Part of the test involves imagining what someone similar to you might have done in the same circumstances if they wanted to meet the deadline.

HMRC will consider your situation on its own merits and the comparison to a hypothetical person will be with someone standing in the same shoes.

HMRC’s guidance indicates that simply asserting that you are suffering from a mental health condition is unlikely to be sufficient. You will need to demonstrate how your condition ‘detrimentally affected your ability to comply with your tax obligation’.

You may want to pre-empt HMRC questioning by sending them evidence at the outset, such as a note from a medical or mental health professional.

‘Ultimately, a common sense interpretation of what represents a reasonable excuse is often a good barometer of its chances of success.

The HMRC list gives the following ‘reasonable excuses’ but they need to be backed up with concrete evidence to prove they are valid, and are not accepted at face value. These include:

• a partner or another close relative died shortly before the tax return or payment deadline;
• taxpayer had an unexpected stay in hospital that prevented them from dealing with their tax affairs;
• taxpayer had a serious or life-threatening illness;
• computer or software failed while preparing online return;
• issues with HMRC online services;
• a fire, flood or theft prevented completion of tax return;
• postal delays that could not have been predicted;
• delays related to a disability or mental illness the taxpayer has;
• unaware of or misunderstood legal obligation; and
• relied on someone elseto send tax returns, and they did not.

The filing deadline for self-assessment tax returns for 2023-24 tax year is 23:59 on Friday 31 January and it is strictly enforced.