On 27 March 1951, Attlee sent Menzies a personal message saying that, while negotiations with the United States for use of the Nevada Test Site were ongoing, work would need to begin if the Monte Bello Islands were to be used in October 1952. Menzies replied that he could not authorise the test until after the Australian federal election, to be held on 28 April 1951, but was willing to allow work to continue. Menzies was re-elected, and the Australian government formally agreed in May 1951. On 28 May, Attlee sent a comprehensive list of assistance that it hoped that Australia would provide. A more detailed survey was requested, which was carried out by in July and August 1951. The British government emphasised the importance of security, so as not to imperil its negotiations with the United States. The Australian government gave all weapon design data a classification of "Top Secret", other aspects of the test being "Classified". Nuclear weapons design was already covered by a D notice in the United Kingdom. Australian D Notice No. 8 was issued to cover nuclear tests.