48Additional services
(1)In this Part “additional service” means any service which consists in the sending of telecommunication signals for transmission by wireless telegraphy by means of the use of the spare capacity within the signals carrying any television broadcasting service provided—
(a)on any frequency assigned under section 65(1) (other than a frequency which, in pursuance of section 73(2), is assigned by the Commission to a local delivery service within the meaning of Part II), or
(b)on any other allocated frequency notified to the Commission by the Secretary of State.
(2)For the purposes of this Part the spare capacity within the signals carrying any such broadcasting service shall be taken to be—
(a)where the service is provided on a frequency falling within subsection (1)(a) above, any part of those signals which is not required for the purposes of the provision of that service and is determined by the Commission to be available for the provision of additional services;
(b)where the service is provided on a frequency notified to the Commission under subsection (1)(b) above, such part of those signals as the Secretary of State may specify when making the notification;
and references in this Part to spare capacity shall be construed accordingly.
(3)The Commission shall, when determining under subsection (2)(a) the extent and nature of the spare capacity available for the provision of additional services in the case of any frequency, have regard—
(a)if it is a frequency on which a Channel 3 service or Channel 5 is provided, to the obligations of the person providing that service as respects the provision of subtitling in accordance with conditions imposed in pursuance of section 35;
(b)if it is a frequency on which Channel 4 is provided, to the need for subtitling to be provided in connection with programmes on Channel 4; and
(c)if it is a frequency falling within either of paragraphs (a) and (b), to any need of the person providing the service in question to be able to use part of the signals carrying it for providing services (other than subtitling) which are ancillary to programmes included in the service and directly related to their contents.
(4)A person holding a licence to provide a Channel 3 service or Channel 4 or 5 shall be taken for the purposes of this Part to be authorised by his licence—
(a)to provide subtitling as mentioned in subsection (3)(a) or (b); and
(b)to provide any such services as are mentioned in subsection (3)(c).
(5)The Secretary of State may, when making any notification under subsection (1)(b), specify a date beyond which the frequency in question is not to be used for the provision of additional services; and any such notification shall accordingly cease to have effect on that date.
(6)In this section—
“allocated frequency” means a frequency allocated to the United Kingdom for the provision of television broadcasting services;
“subtitling” means subtitling for the deaf provided by means of a teletext service; and
“telecommunication signals” means anything falling within paragraphs (a) to (d) of section 4(1) of the [1984 c. 12.] Telecommunications Act 1984 (meaning of “telecommunication system”).