Interest Charged after I updated my Self Assessment

I found a mistake in my tax return for 2022/2023, and updated it few days ago. Addtional tax due appeared today. However, alongside the new tax due, there is an interest payment. Why I am charged interest?

Im not HMRC, am a tax acct. Its because, the additional tax was technically due either by 31 January 2024, or, if you were liable to payments on account January and July 2023, and if liable for payments on account for 2024/25 then the first also was 31 January 2024.In all cases, the additional tax is being paid late, hence interest.

Hi Kwok Ching Tsui,
The balance for the 2022/23 Self Assessment was due 31 January 2024.
If the amendment has increased the balance due then this payment would have been due by 31 January 2024 and as now late interest has been charged
You can object to the interest charged in writing to:
HMRC, Self Assessment & PAYE, BX9 1AS UK.
Thank you.