Untaxed Interest - P800 vs Self Assessment

[ychi]

In early September I submitted my Self Assessment Tax Return online for 2018-2019, declaring interest received fully (sole and joint accounts). This was above the £1000 tax free allowance and as such the calculation show tax to be paid, which I intend to pay before the Jan 2020 deadline.

I have now received my P800 and as part of the calculation, 'Untaxed Interest' is included and of a lessor amount than above (I assume this is gathered directly from banks and of sole accounts only). It seems as HRMC has not used the information in my tax return. The tax owing to be automatically collected via PAYE.

If I pay the tax owing based on the self assessment calculation in full and the P800 amount is being automatically collected from PAYE then I will effectively be paying twice.
What should I do?

1. Do I pay my self assessment amount in full and HMRC will show a overpayment in next years calculations?
2. Do I pay less on self assessment?
3. Do I raise this with HMRC.

Thanks

Chi

[jerome.lane]

Double check your figures, make sure the tax return was processed and then take it up with HMRC.
Does the only interest included by HMRC equal your sole account interest? Is it a mistake on their part?
Look out for things like ISA's etc.
If you intended paying the tax by next January, HMRC wouldn't try collecting through PAYE so something isn't right between how you think you've submitted your return and how HMRC have processed it.
You might want to get an adviser to look over the return you prepared and the P800.

[robbob]

I have now received my P800 and as part of the calculation, 'Untaxed Interest' is included and of a lessor amount than above (I assume this is gathered directly from banks and of sole accounts only). It seems as HRMC has not used the information in my tax return. The tax owing to be automatically collected via PAYE.

HMRC are a bit of a joke in this regard - if you have submitted a self assessment return then the p800 should not have been issued, simply ring them up and advise you have submitted self assessment return and ask them to cancel the p800. This can get messy if there are associated tax code changes that have been incorrectly linked to this incorrect calculation so bear that in mind.

As to how they arrived at the interest received figure you can ask them - they have advised though that this information is now likely to come directly from the banks or building societies so presuming its not simply a follow on amount from previous years included in your code i would guess it is as you say some of your totals have been included and some missed - their calcs are probably about as reliable as a Tesla on autopilot driving around newcastle city centre friday night at 12.30pm.

[maths]

As Robbob points out quote from HMRC website: "You will not get a P800 if you’re registered for Self Assessment. Your bill will be adjusted automatically if you’ve underpaid or overpaid tax".

Contact HMRC.

[ychi]

Thanks for the advice. I've contacted HMRC and they will withdraw the P800. They advised that the bank interest value came directly from banks but could provide a list of institutions for me to compare.