Regulation 68 Priority between communications
Subject to the next paragraph, where a controller receives two or more conflicting communications it is the duty of the controller to:
act on the communications in the order of their receipt; or
(in the event that they are received simultaneously or their time of receipt cannot be determined) to reject them.
Communications shall not be regarded as conflicting for this purpose solely because one communication amends or countermands the other.
Paragraph (1) shall apply unless it is not reasonably practicable, as a result of the manner in which communications received by the controller are processed, for the con-troller to comply with that paragraph.
Where paragraph (1) does not apply:
communications shall be regarded as having been properly acted upon by the controller notwithstanding that they have not been processed in order of their receipt or issue provided that they have been acted upon in the normal course of processing; and
the controller shall not be in breach of any duty of his or its under these Regulations by failing to act upon the communications in the order in which they have been received or made.