Australian Prime Minister Robert Menzies asked the British government to notify Germany that Australia was an associate of the United Kingdom. On 3 September 1939, Britain declared war when its ultimatum for Germany to withdraw from Poland expired. Because the Statute of Westminster had not yet been ratified by the Australian parliament, any declaration of war by the UK applied to Australia by default. After the British informed Menzies of the declaration of war, the Governor-General of Australia issued a proclamation of the existence of war in Australia. Menzies' support for the war was based on the notion of an imperial defence system, upon which he believed Australia relied and which would be destroyed if the UK was defeated. This position was generally accepted by the Australian public, although there was little enthusiasm for war.