15.—(1) An admission order shall authorise the reception, detention and treatment of the patient concerned and shall remain in force for a period of 21 days from the date of the making of the order and, subject to subsection (2) and section 18(4), shall then expire.

(2) The period referred to in subsection (1) may be extended by order (to be known as and in this Act referred to as “a renewal order”) made by the consultant psychiatrist responsible for the care and treatment of the patient concerned for a further period not exceeding 3 months.

F19[(3) (a) The period referred to in subsection (1) may be further extended by order made by the consultant psychiatrist concerned for a period not exceeding 6 months beginning on the expiration of the renewal order made by the psychiatrist under subsection (2) and thereafter may be further extended by order made by the psychiatrist for periods each of which does not exceed 6 months (each of which orders is also referred to in this Act as "a renewal order").

(b) Subject to paragraphs (c) and (d), a patient detained pursuant to any renewal order made under paragraph (a) for a period exceeding 3 months, or his or her legal representative, on the instructions of the patient or on the representative’s own initiative, may make one application per renewal order period, in a form specified by the Commission for the purpose, in respect of that renewal order to the Commission to have his or her detention reviewed by a tribunal in accordance with the provisions of section 18.

(c) An application referred to in paragraph (b) shall be made to the Commission not earlier than 3 months from the date on which the renewal order concerned was made under paragraph (a).

(d) For the purposes of a review conducted pursuant to an application referred to in paragraph (b), subsection (1) of section 18 shall be read as if paragraph (a) of that subsection were deleted therefrom and the following paragraph were substituted therefor:

"(a) if satisfied that the patient is suffering from a mental disorder, affirm the order, or"]

(4) The period referred to in subsection (1) shall not be extended under subsection (2) or (3) unless the consultant psychiatrist concerned has not more than one week before the making of the order concerned examined the patient concerned and certified in a form specified by the Commission that the patient continues to suffer from a mental disorder.