PAYE tax code reduced by £421 for savings interest, but not earning enough to be taxed?

My new tax code for 24/25 has a tax code of C1117 due to marriage tax allowance and other things. But I can see they have reduced it by £421 to account for savings interest. Due to being a low earner I do not earn over the threshold so not only get the personal savings allowance of £1000, I should also get £5000 starter rate of tax, meaning all the interest I earned last year, which is under £6k, should be tax free. How can I get this reduction removed? and if it does not get removed, how will I get the additional tax back if its taken by PAYE? Why would HMRC levy this charge when I am not required to pay tax on my savings?

Hi,

As you correctly say, your £421 savings income will not be subject to tax, as you have the additional £1000 savings allowance and £5000 starting rate. The £421 is applied to your code for your information only, should your income increase to the extent that the £421 reduction causes you to pay tax, that £421 reduction will automatically be removed.

Thank you.