HMRC have updated their guidance on Rates and allowances: Inheritance Tax thresholds and interest rates, to show the higher interest rates applying from 13 April 2023.
The rate charged on late payments is set at 6.75%.
The rate paid on repayments is set at 3.25%.
In each case, this is the third increase this year. The rates at the start of 2023 were 5.5% and 2% respectively.