HC Deb 24 May 1965 vol 713 c18W
Mr. Eldon Griffiths

asked the Postmaster-General if he will estimate the proportion of subscriber trunk dialling telephone calls which now fail to reach the number dialled at the first attempt; and to what causes he attributes the failures.

Mr. Benn

In addition to calls which reach the number dialled but where the subscriber is engaged or does not reply, about 7 per cent of STD call attempts fail because the caller makes a mistake in setting up his call; about 6–5 per cent. fail for technical reasons; and about 3–5 per cent. fail because of congestion in the network. Congestion occurs mainly because trunk traffic has grown extremely rapidly in the last two or three years. Many technical faults are due to the continuing use of old and obsolete equipment. A large capital programme is now underway to modernise and expand the system. Installation of new equipment must necessarily take some time before results can be obtained.