Regulation 5.4 Rule 5
The discount rate for the whole of the discount period to be used in calculating the discount factor shall be determined as follows—
(a)
in a case where the sterling discount rate is to apply (see Rule 1), the discount rate shall be found from the formula—
(b)
in a case where a foreign currency discount rate is to apply (see regulation 5), the discount rate shall be found from the formula—