The War Illustrated, Volume 1, No. 2, Page 44, September 23, 1939.

Air Raids and Warnings: Facts to Remember

From a letter to "The Times" by Brig.-Gen. Sir Henry Page-Croft, M.P., dated September 6.

Sir,- It is important that the technique of meeting enemy air raids should be perfect as possible, and it is desirable that all citizens of London should realise that there is no possible danger to themselves from bombs until our anti-aircraft guns have been definitely heard to be firing. The only possible exception to this would be in very rough or very cloudy weather should an enemy aircraft succeed in penetrating our magnificent defences without being observed.

We may take it, therefore, as almost certain that no citizen is in any danger until gun-fire has been heard. This gun-fire will be unmistakable, as there will be many short, sharp, loud barks from the guns, and if we are wise we regard this as a joyous sound in that it indicates that our defences, so admirable in their preparation, are all at work. Shelter should, of course, be taken from the danger of splinters or fuses form our own shells when firing starts.

Citizens should also remember that should a bomber penetrate the defences there will probably be at least 50 British anti-aircraft gun reports to one enemy bomb, and it is important that all should realise the loud friendly sound of the anti-aircraft fire as opposed to what will be a comparatively rare, deep, muffled rumbling of an exploding bomb.

The next thing we have to remember is that in the vastness of London the odds against a bomb reaching one’s own immediate neighbourhood are very great, and to recall the comforting thought that in the whole three years of the war in Spain the total deaths of civilians from air attacks in no way equalled the number of deaths on the road in England due to motor-car accidents, while the number of injured in that prolonged war was only a small fraction of injured on our roads in a single year.

Once these facts are appreciated, it then remains important that Hitler should disturb our normal lives as little as possible, and it may be hoped, with improved experience, all-clear signals may come through more speedily...

Yours, & c, HENRY PAGE-CROFT.