11.—(1) A payer must pay an invoiced amount to the Settlement Body by no later than 5.00 p.m. on the payment due date.
(2) A payment made after 5.00 p.m. is to be treated as having been made on the following day.
(3) Where a payer has not paid the invoiced amount to the Settlement Body in full as required by paragraph (1), the payer must pay the Settlement Body simple interest at the rate specified in paragraph (5) (“late payment interest”) on the outstanding balance of the invoiced amount from and including the payment due date until (but not including) the date of payment.
(4) Where a payer disputes an invoiced amount under Chapter 2 of Part 10 of the Principal Regulations—
(a)if the decision of the Settlement Body under that Part is that the invoiced amount is reduced but not extinguished, late payment interest accrues on the reduced amount from and including the payment due date until (but not including) the date of payment;
(b)if the decision of the Settlement Body under that Part is that the invoiced amount is extinguished, no late payment interest accrues in respect of the invoiced amount.
(5) The rate at which late payment interest is payable is 5 per cent per annum over the Bank of England base rate in force on the 30th June (in respect of interest which starts to run between 1st July and 31st December) or the 31st December (in respect of interest which starts to run between 1st January and 30th June) immediately before the date on which the interest starts to run.
(6) In paragraph (5), “Bank of England base rate” means—
(a)the rate announced from time to time by the Monetary Policy Committee of the Bank of England as the official dealing rate, being the rate at which the Bank is willing to enter into transactions for providing short term liquidity in the money markets; or
(b)where an order under section 19 of the Bank of England Act 1998(1) is in force, any equivalent rate determined by the Treasury under that section.