§ Mr. Churchill
To ask the Secretary of State for Defence further to his reply of 25 February to the hon. Member for Davyhulme in regard to the levels of ionising radiation to which members of Her Majesty's forces were exposed in the course of the British atmospheric nuclear weapons test and experimental programme(a) what proportion of those participating were issued with personal dosimeters, (b) what was the highest dose to which any individual was exposed, (c) how this level compared with the maximum permitted dosage and (d) how this level compares with the current maximum permitted dosage.
§ Mr. Sainsbury
About a quarter of participants were issued with dosimeters. The highest exposure recorded, for two individuals, was 30R, equivalent in modern dosimetric terms to 200 milliSieverts effective dose equivalent. The current United Kingdom limit for radiation workers is 50 mSv per annum. ICRP recommends that planned special exposures above the annual limit should not exceed 250 mSv in the lifetime of any individual. The most recent NRPB guidance suggests that the risks associated with an average of 15 mSv per annum, corresponding to about 300 mSv in a working career of 20 years, are not unacceptable, although it recommends that all exposure should be "as low as reasonably practicable", the ALARP principle.