(1) If the whole or any part of a financial penalty or costs order is not paid by the time by which it is required to be paid, the unpaid balance from time to time carries interest at the rate for the time being specified in section 17 of the Judgments Act 1838 [1838 c. 110, amended by S.I. 1993/564 and S.I. 1998/2940.].

(2) Where a financial penalty or costs order, or any part of a financial penalty or costs order, has not been paid by the time when it is required to be paid and -

(a) no appeal has been made in respect of that penalty or costs order by the relevant date; or

(b) an appeal has been made in respect of that penalty or costs order, but has been determined or withdrawn,

the competent authority may recover from the person on whom the penalty or costs order was imposed, as a debt due to the competent authority, any of the penalty or costs order and any of the interest which has not been paid.