Why am I being asked for interest for tax?

Until June 2023 I received and paid tax on income from rental. I always pay my tax in good time; I do not have enough money to make payments on account so always set that to zero. I have just now received a request for interest of £79.82 with a threatening reminder "Interest is running". Is this interest on the payment on account whihc HMRC think I should have paid last year? In other words, interest on tax which HMRC wanted me to pay in advance?

Hi,

As we would need to access your record to check why interest has been charged you will need to contact our Self Assessment team.

Self Assessment: general enquiries

Thank you.

Im not HMRC, am a tax acct. If you are due to make payments on account and you reduce these, but tax is due for the year, HMRC automatically charge interest back to the original payment dates, so interest on 50% of the tax from the preceeding January and in terest on 50% of the tax from the preceeding July, i.e. both preceeding the January after. Payments on account are not "optional"...if they are calculated as due and you reduce them (in your words set them to zero) and leave less in charge than the tax that is due for the year you will always incur interest, and that interest is not appealable.