SDLTM85945 - Interest on repayment of overpaid tax
FA03/S89 applies to any repayment of tax and any repayment of a penalty overpaid.
The relevant dates for the computation of interest payable are from the date the payment is lodged with HMRC until the date when the order for repayment of that amount is issued.
Interest paid by HMRC is not treated as income, or profits or gains for tax purposes.
The rate of interest is fixed by statutory instrument and is the rate applicable under FA89/S178.
The current rate can be found at Interest rates for late and early payments - GOV.UK (www.gov.uk).