§ Mr. Pavittasked the Secretary of State for the Home Department, (1) in view of his responsibility with regard to civil defence, what estimate he has made of 128W the proportion of the total buildings within the Metropolitan boundaries which would be damaged, but salvageable, if a 10-megaton nuclear bomb fell in the centre of each of the following cities, London, Glasgow, Manchester, Birmingham, Cardiff, and Bristol;
(2) in view of his responsibility with regard to civil defence, what estimate he has made of the proportion of the total buildings within the Metropolitan boundaries which would be damaged past repair if a 10-megaton nuclear bomb fell in the centre of each of the following cities, London, Glasgow, Manchester, Birmingham, Cardiff, and Bristol; and if the civil defence personnel in those cities are aware of the extent of this possible damage.
§ Mr. R. A. ButlerIt is not practicable to give precise estimates, but, as a general indication, houses within an average radius of up to five miles from the point of burst of a 10-megaton bomb might be destroyed or damaged beyond repair, and severe to moderate damage might be caused up to a further eight males. This and other information about the effects of nuclear attack is contained in the training manual "Nuclear Weapons".
§ Mr. Pavittasked the Secretary of State for the Home Department (1) if, in the event of a firestorm following a nuclear explosion, civil defence arrangements include defence against asphyxiation in shelters caused by the using up of oxygen in the conflagration and the consequent deprivation of oxygen to those in shelter.
(2) In view of his responsibility with regard to civil defence, what estimate he has made of the radius of the circle of the firestorm consequent upon the surface detonation of a 10-megaton nuclear bomb in a built-up area.
§ Mr. R. A. ButlerFor the reasons explained in the publication "Nuclear Weapons" firestorms after nuclear attack are unlikely in most British cities, and the risk would be reduced by adopting the precautions outlined in this manual.
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§ Mr. Pavittasked the Secretary of State for the Home Department what study has been made of the length of time that the girders of the large office blocks recently built in London would remain centres of radiation after the buildings had been destroyed in a nuclear war; and what steps would be taken by civil defence units to decontaminate them.
§ Mr. R. A. ButlerThere is no reason to suppose that girders would present a special radiation hazard. Within the area in which buildings had been destroyed, the principal source of radiation would be from fission products deposited by the explosion.
§ Mr. Pavittasked the Secretary of State for the Home Department what studies have been made recently on the possible extent of leukaemia and bone tumours in British survivors in the event of a nuclear war; and whether the results of all such studies have been made available to civil defence personnel.
§ Mr. R. A. ButlerReports on the hazards to man of nuclear and allied radiations were issued by the Medical Research Council in 1956 (Cmd. 9780) and in 1960 (Cmd. 1225). These reports include reference to the possible long-term effects of radiation on the individual in the event of nuclear war. Information based on the first of these reports is given in the training manual "Nuclear Weapons" and I am advised that there is nothing in the second report which requires any revision of the relevant paragraphs.
§ Mr. Pavittasked the Secretary of State for the Home Department what arrangements are envisaged by Civil Defence units to cope with internal radiation of the thyroid and gastro-intestinal tract by ingestion of contaminated food and water following a nuclear attack.
§ Mr. R. A. ButlerHome defence preparations aim at reducing to a minimum the risks to which the hon. Member refers by measures for the detection and control of contaminated food stocks and public water supplies. The increased expenditure on home defence announced in the recent Defence White Paper includes further provision for these purposes.
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§ Mr. Pavittasked the Secretary of State for the Home Department, in view of his responsibility with regard to civil defence, what estimate he has made of the time which elapses between the surface blast of a 10-megaton nuclear bomb and the fall-out at a distance of 10 miles downwind from the explosion; and what protective steps should be taken in that period.
§ Mr. R. A. ButlerAbout half-an-hour. The publication "Nuclear Weapons" gives guidance as to the protective steps which should be taken during this period, as well as before an attack.