Following Britain’s declaration of war on 4 August 1914, men and materials were immediately offered by all Dominion governments. The commitment of the Dominions was affirmed in the Canadian House of Commons by Prime Minister Sir Robert Borden: ‘As to our duty, all are agreed; we stand shoulder to shoulder with Britain and the other British dominions in this quarrel … not for love of battle, not for lust of conquest, not for greed of possessions, but for the cause of honour.’ Until the 1931 Statute of Westminster, Britain retained control of Dominion foreign policy, including the ability to declare war independently. Therefore, unlike at the outbreak of the Second World War, former Canadian Prime Minister Sir Wilfrid Laurier’s 1910 maxim, ‘When Britain is at war, Canada is at war. There is no distinction’, was the legal arrangement for all Dominions in August 1914.

The Dominions had the autonomy, however, to decide the scope of men and materials offered to the imperial war effort. New Zealand formally committed a contingent of 8,000 soldiers on 30 July, with Canada following suit with a pledge of 25,000 men on the 31st. On 5 August, Australia pledged a force of 20,000 men. On 4 August, South Africa, alone among Dominions in that it was still garrisoned by British troops, immediately offered to replace British regiments with UDF units. The last British troops left South Africa on 10 August to supplement the British Expeditionary Force (BEF) bound for the Western Front. On 8 August, Newfoundland pledged ‘500 troops for land service abroad’ and doubled its Naval Reserve quota to 1,000 sailors.