The government planned to voluntarily evacuate four million people—mostly women and children—from urban areas, including 1.4 million from London. It expected about 90% of evacuees to stay in private homes, and conducted an extensive survey to determine available space. Detailed preparations for transporting them were developed. A trial blackout was held on 10 August 1939, and when Germany invaded Poland on 1 September a blackout began at sunset. Lights would not be allowed after dark for almost six years, and the blackout became by far the most unpopular aspect of the war for civilians, more than rationing.:51,106 The relocation of the government and the civil service was also planned, but would only have occurred if necessary so as not to damage civilian morale.:33