(1) A person who is a party to an agreement to which section 73 applies shall be subject to the requirements of this section at any time when -
(a) the target company is a public limited company, and he knows it to be so, and
(b) the shares in that company to which the agreement relates consist of or include shares comprised in relevant share capital of the company, and he knows that to be the case, and
(c) he knows the facts which make the agreement one to which section 73 applies.
(2) Such a person shall be under obligation to notify every other party to the agreement, in writing, of the relevant particulars of his interest (if any) apart from the agreement in shares comprised in relevant share capital of the target company -
(a) on his first becoming subject to the requirements of this section, and
(b) on each occurrence after that time while he is still subject to those requirements of any event or circumstances within section 67(1) (as it applies to his case otherwise than by