13.—(1) The subsidiary requirements set out in the Second Schedule shall apply to an undertaking or group of undertakings, and a European Works Council shall be established—

(a) where the central management and the Special Negotiating Body so agree,

(b) where the central management refuses to commence negotiations within six months of a request referred to in section 10 (1), or

(c) where after the expiration of a period of three years from the date of the request, the parties are unable to conclude an agreement and the Special Negotiating Body has not taken the decision provided for in section 11 (4).

(2) Where the subsidiary requirements apply to an undertaking or group of undertakings, the central management shall as soon as practicable, but in any case not later than six months after they first become applicable, comply with the requirements.