Exempt agreements
21.—(1) A qualifying agreement to which this Chapter applies is exempt if—
(a)it contributes to the attainment of one or more of the bus improvement objectives,
(b)it does not impose on the undertakings concerned restrictions which are not indispensable to the attainment of those objectives, and
(c)it does not afford the undertakings concerned the possibility of eliminating competition in respect of a substantial part of the services in question.
(2) In any proceedings in which it is alleged that the prohibition in article 19 is being or has been infringed by a qualifying agreement any undertaking or association of undertakings claiming the benefit of paragraph (1) must bear the burden of proving that the conditions in that paragraph are satisfied.