(1) If a document contains a statement by a person referred to in subsection (2) asserting that an act has been done, or is or was proposed to be done, by another person, being an act (the "relevant act") that relates to -
(a) the entry into or the making or implementation of an agreement or decision, or the engaging in of a concerted practice, the subject of proceedings under this Act, or
(b) the doing of the act or acts that constitute an abuse of a dominant position, the subject of proceedings under this Act,
then, subject to the conditions specified in subsection (3) being satisfied, that statement shall be admissible as evidence in the proceedings referred to in paragraph (a) or (b) that the relevant act was done by that other person or was proposed (at the time the statement was made or, as the case may be, at a previous time) to be done by him or her.
(2) The person mentioned in subsection (1) is a person who has done an act of the kind referred to in that subsection in rel