139. (1) The Commission may require any person (other than an online platform or a buyer of an online political advertisement) who possesses information or possesses or controls a document or relevant thing that is relevant to the performance by the Commission of any of its functions under this Part to provide the information, document or thing to the Commission and, where appropriate, may require the person to attend before it for the purpose of the performance by the Commission of any of those functions.

(2) A person referred to in subsection (1) shall co-operate with the Commission in its performance of its functions and answer fully and truthfully any question put to him or her by it.

(3) Where a person fails to comply with a requirement made under subsection (1), the Commission may apply to the High Court, on notice to the person, and the High Court may—

(a) order the person to comply with the requirement, and

(b) include in the order any other provision it considers necessary to enable the order to have full effect.

(4) If the person fails to comply with an order of the High Court under subsection (3), the Court may treat the failure for all purposes as if it were a contempt of the Court.

(5) Any information, document or relevant thing provided by a person in accordance with a requirement made under subsection (1) shall not be admissible in any criminal proceedings against the person, and this shall be explained to the person in ordinary language by the Commission.

(6) The power under subsection (1) is in addition to any other power conferred on the Commission, the chief executive, an authorised officer or member of staff of the Commission by this Part.