s 57 Conditions to secure access to telephone numbers
(1) General conditions may impose such requirements as OFCOM consider appropriate for securing that every end-user of a public electronic communications service is able, by means of that service— (a) to make calls or otherwise transmit electronic communications to every normal telephone number; and (b) to receive every call or other electronic communication that is made or transmitted to him using such a service from apparatus identified by a normal telephone number. (2) A normal telephone number is one which— (a) has been made available, in accordance with the National Telephone Numbering Plan, as a number to be used for the purpose of identifying the destination for, or the recipient of, electronic communications; and (b) is for the time being— (i) a number adopted by a communications provider to be used for such a purpose; or (ii) a number in use for such a purpose by a person other than a communications provider to whom it has been allocated in accordance with conditions under section 59. (3) In this section “ electronic communication ” has the same meaning as in section 56.