§ Mr. Denvilleasked the Secretary of State for the Home Department whether he will consider shortening the air-raid siren and the all clear to one-third of the present time or, as an alternative, cutting them out altogether.
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§ Mr. H. MorrisonThe period of sounding the sirens has already been reduced from two minutes to one minute, and I do not think that a reduction to the extent suggested would allow the difference between the "Alert" and "Raiders passed" to be sufficiently noticeable, especially inside buildings. There are also technical difficulties where sirens are automatically controlled, as in large towns. The advantages of the alternative of not using the sirens, and therefore giving no public warning, are very debatable, but, as I have already said, we will be guided by experience.