HC Deb 19 February 1958 vol 582 c146W
67. Mr. Llewellyn

asked the Postmaster-General whether he will consider creating a single figure or single letter telephone alarm for use by callers who suspect the presence of housebreakers which will obviate a caller's need to speak to the Exchange before being put through to the police.

Mr. K. Thompson

No. Three figures, "1", "9" and "0", are already reserved for special purposes and we could not use any of the others without changing all the subscribers' numbers which begin with the figure or letter selected.