Regulation 2(1)(c) of Government Gazette 17939 of 25 April 1997, made under section 26 of the Road Accident Fund Act 56 of 1996, is peremptory and not ultra vires. The regulation requires a claimant in an unidentified vehicle case to submit an affidavit to police within 14 days of being in a position to do so, if reasonably possible. A claimant is 'in a position' to submit an affidavit when physically and mentally capable and in possession of the necessary facts about the accident; subjective knowledge of the regulation's requirements is not necessary. If it is not reasonably possible to submit the affidavit within 14 days of being in such position, the period is extended only for so long as it is not reasonably possible, but no longer. The regulation is peremptory because it prescribes a penalty for non-compliance (the Fund incurs no liability). The regulation is intra vires because it is regulatory and procedural in nature, designed to eliminate fraud and facilitate proof in cases where fraud is more likely and the Fund's ability to controvert allegations is limited, which is ancillary to the Act's objectives. An affidavit is only 'submitted' to police when it is actually furnished to them for their consideration, not merely sworn before a police officer acting as commissioner of oaths.