§ Mr. Trotterasked the Secretary of State for Industry what is the approximate number of STD telephone calls per annum which fail from technical faults, and the percentage of such failures to the total number of STD calls.
§ Mr. Gregor MackenzieThe Post Office tells me that it is not possible to estimate the actual number of STD calls which are attempted, but large sample 459W observations on call attempts show that about one in every 27 fail because of plant defects. This figure has been reducing for some years. Successful calls are metered and for the year 1973–74 numbered about 1,860 million.