§ Mr. Lubbockasked the Postmaster-General if he will circulate in the OFFICIAL REPORT a list of the telephone exchanges outside Greater London to which outside extensions from Central London exchanges cannot be provided.
§ Mr. BennNo. Such a list could only be compiled after the very considerable labour of examining the feasibility of outside extensions between subscribers connected to about 50 exchanges in Central London and those served by the 5,600 exchanges, or so, outside Greater London. I should be happy to look at any specific174W requirement which the hon. Member has in mind.
The public telephone system comprises about: 6,000 local exchanges; 300 separate trunk and auto-manual exchanges; 55,000 trunk circuits; 600,000 short trunk and junction circuits, and the local lines to about 6¼ million subscribers. The system is designed primarily to connect calls from an originating subscriber's telephone through his local exchange to the terminating subscriber's telephone through his local exchange. Depending on the locations a call may be switched through several intermediate exchanges.
The feasibility of extending such calls to a third destination over an external extension from the terminating subscriber's telephone depends on whether the extra plant involved will allow satisfactory signalling and speech transmission. This can only be established by detailed examination in each instance. If extended calls are impracticable the calling subscriber can, of course, telephone the ultimate destination directly.