The following article contains an answer for the question: What is the name of the empire about which it was feared it could not survive a simultaneous attack by both Germany and Japan? , can you please find it? 

The changing world order that the war had brought about, in particular the growth of the United States and Japan as naval powers, and the rise of independence movements in India and Ireland, caused a major reassessment of British imperial policy. Forced to choose between alignment with the United States or Japan, Britain opted not to renew its Japanese alliance and instead signed the 1922 Washington Naval Treaty, where Britain accepted naval parity with the United States. This decision was the source of much debate in Britain during the 1930s as militaristic governments took hold in Germany and Japan helped in part by the Great Depression, for it was feared that the empire could not survive a simultaneous attack by both nations. The issue of the empire's security was a serious concern in Britain, as it was vital to the British economy.In 1919, the frustrations caused by delays to Irish home rule led the MPs of Sinn Féin, a pro-independence party that had won a majority of the Irish seats in the 1918 British general election, to establish an independent parliament in Dublin, at which Irish independence was declared. The Irish Republican Army simultaneously began a guerrilla war against the British administration. The Anglo-Irish War ended in 1921 with a stalemate and the signing of the Anglo-Irish Treaty, creating the Irish Free State, a Dominion within the British Empire, with effective internal independence but still constitutionally linked with the British Crown. Northern Ireland, consisting of six of the 32 Irish counties which had been established as a devolved region under the 1920 Government of Ireland Act, immediately exercised its option under the treaty to retain its existing status within the United Kingdom.

the British Empire