Non taxed interest - how do I find out where HMRC has obtained this information.

There is an amount of untaxed interest noted on my tax account and it has reduced my personal allowance. The figure is just £100 and I have no idea where this has come from, I do have untaxed interest from bank savings accounts but combined it is less than the £1k allowed but is over £100… I am very confused. Previous year shows an underpayment of tax but I am unable to how this has been calculated as I am sure I paid all tax due.

Hi Maureen Nicolls,
To review this you will need to contact HMRC:
Income Tax: general enquiries
Thank you. 

Can you tell me how to contact HMRC as using the phone is pointless. Is there an option to send an email or secure message?

Hi,

There is the option to webchat.

Self Assessment: general enquiries

When you open the link, if you click on Ask HMRC online, we will check if a webchat adviser is available to chat.

Thank you.