'Cursed by my mother-in-law': HMRC reveals the worst excuses for late tax returns

With the tax return deadline fast approaching, some taxpayers will face a genuine struggle to file their self-assessment on time. Others, however, encounter more dubious delays, as HMRC's list of strangest excuses for late submissions reveals.

Tax returns are due on 31 January and submitting even one day late could land you a £100 fine. One would-be taxpayer pleaded for an exemption on the basis they had been placed under a witch's curse - cast by their mother-in-law.

Tragic as the tale may be, HMRC didn't buy it. This attempt at avoiding a fine was included in a list of 'unbelievable excuses', along with the most 'dubious' expenses claims, released by HMRC ahead of the upcoming deadline.

Read on to see more of last year's least convincing excuses for filing late, and find out what to do if you genuinely can't meet the tax return deadline.

HMRC's worst excuses for late submissions

While you're racing to finish your self-assessment forms on time, spare a thought for the unfortunate taxpayers who had to contend with frozen fingers and magical family members.

Last year, HMRC received these creative excuses for missing the deadline:

1. 'My mother-in-law is a witch and put a curse on me.'
2. 'I'm too short to reach the post box.'
3. 'I was just too busy - my first maid left, my second maid stole from me and my third maid was very slow to learn.'
4. 'Our junior member of staff registered our client in Self Assessment by mistake because they were not wearing their glasses.'
5. 'My boiler had broken and my fingers were too cold to type.'

Perhaps unsurprisingly, HMRC didn't accept any of these excuses.

What is the penalty for a late tax return?

If you don't submit your 2017-18 self-assessment form online by midnight on 31 January this year, you'll be issued an automatic £100 fine.

After the initial fine, your penalty will increase every day until you file your return:

If you were hoping to file a paper tax return, the 31 October deadline has already passed. However, you can still opt to file online until the end of January.

• Find out more:online tax returns

What is a reasonable excuse for an HMRC penalty?

Though you may not be suffering from a witch's curse, you might have a genuine reason for missing the deadline. You can appeal against HMRC's fines, but you'll need to provide a 'reasonable excuse'.

HMRC has said it will consider cancelling your penalty if any of the following interfered with your filing process:

• the death of a partner or family member.
• serious illness.
• fire, flood or theft.
• computer failure or issues with HMRC online services.

The HMRC website has a full list of reasonable excuses it's willing to accept, though each appeal is decided on a case-by-case basis.

HMRC also sets out common excuses that won't be accepted, including relying on someone else, or finding the HMRC system to difficult to use.

If you do find yourself in circumstances that prevent you from meeting the deadline, let HMRC know as soon as possible, preferably before the deadline has passed.

And if you're issued with a penalty you don't think is justified, kick offthe appeal processas soon as you receive the fine.

• Find out more:late tax returns and penalties for mistakes

HMRC's top five optimistic expenses claims

If you're self-employed, you may be able to claim certain business expenses to lower your tax bill.

But HMRC also received a number of dubious expenses claims last year, including:

1. a 55-inch TV and soundbar for a carpenter to help him price jobs.
2. a five-year supply of woolly underwear.
3. a year's pet insurance.
4. a year's subscription to a streaming service for background music.
5. a family holiday to Nigeria.

Once again, HMRC rejected all these claims.

What expenses can I claim on my tax return?

When you file a self-assessment return, the tax you owe is calculated based on your annual profits. Since earning money often requires spending money, HMRC allows you to deduct business expenses from your taxable profits in order to lower your final bill.

Figuring out what you can and can't claim can be complicated, and it differs depending on your source of income:

Self-employed workers and small business owners

In general, the costs of business trips fall under expenses.

If you use business premises, you can claim the costs of heating, lighting and general maintenance. When working from home, you can claim a proportion of these costs.

If you have employees, their salaries can be deducted from your profits.

You can find out more in our guide: how tax-allowable expenses work for the self-employed

Landlords

As a landlord, you can claim back your rental property's running costs, including buildings insurance, utility bills and cleaning fees for communal areas.

For the 2017-18 tax year, you can deduct 75% of your mortgage interest from your profits, though this will reduce over coming years and eventually be phased out. It's beingreplaced by a 20% tax crediton your mortgage interest instead.

We explain how this works in our guide:how rental income is taxed

Need help with your tax return?

For help with your tax return, Which? offers an easy-to-use, jargon-free tax calculator, which you can use to tot up your expenses, work out your bill, and submit directly to HMRC for a small fee.