Please click here to view the following current rates from April 2012.
Interest on overdue tax
Interest on all unpaid tax is charged at the same rate. The formula is Bank base rate plus 2.5% which gives a present rate of 3%. There is one exception: Quarterly instalments of corporation tax bear interest at only 1.5%.
Interest on all overpaid tax is payable at the same rate. The formula is Bank base rate minus 1% but with an overriding minimum of 0.5% which applies at the present time.
Official rate of interest
From 6 April 2010: 4%