(1) A person shall neither use, nor instigate the use of, a public electronic communications service for the purposes of making unsolicited calls for direct marketing purposes where—
(a) the called line is that of a subscriber who has previously notified the caller that such calls should not for the time being be made on that line; or
(b) the number allocated to a subscriber in respect of the called line is one listed in the register kept under regulation 26.
(2) A subscriber shall not permit his line to be used in contravention of paragraph (1).
(3) A person shall not be held to have contravened paragraph (1)(b) where the number allocated to the called line has been listed on the register for less than 28 days preceding that on which the call is made.
(4) Where a subscriber who has caused a number allocated to a line of his to be listed in the register kept under regulation 26 has notified a caller that he does not, for the time being, object to such calls being made on that line by that caller, such calls may be made by that caller on that line, notwithstanding that the number allocated to that line is listed in the said register.
(5) Where a subscriber has given a caller notification pursuant to paragraph (4) in relation to a line of his—
(a) the subscriber shall be free to withdraw that notification at any time, and
(b) where such notification is withdrawn, the caller shall not make such calls on that line.