underpaid tax - what should I do?

[lauraauroral]

Hi,

Am preparing for mortgage application so have been looking at my figures etc. Part of my income is from self employment so I have to an annual tax return.

I have noticed that I made a mistake on my 2019-20 tax return and paid about £1200 to little in tax. This has not been picked up my HMRC and I only know because I have just discovered my error!

What do I do? Do I call, fess up and pay the £1200. Will they throw a load of interest and fees at me?

What is the likelihood of HMRC identifying this error 4 years on?

aaaargh, I hate money

Definitely fess up and call them. It’s a genuine mistake so hopefully they won’t penalise you. Not only is it the right thing to do morally (you owe the tax) but surely the worry of it eventually being picked up is not worth it.

Have you underdeclared your income or is it a calculation error?

calculation error - purely a typo/brain freeze on my part

Do you need to show the extra income for your mortgage ?

No I won’t need to

So there's no rush. The self-assesment helpline is closed for the summer, back open mid september.

I'm 99.9% sure they wont find out about your error themselves.