Britain breaks off relations with Bulgaria

According to the British chronology of the war and the British official history of naval operations, on 13 October 1915 Great Britain broke off diplomatic relations with Bulgaria. It was the last step before war. For a month Bulgaria had been bound by a secret alliance with Germany, its army was mobilised and stood on the Serbian border, and in London no one any longer believed that Sofia could be held back.

The breach was a process rather than a single act, and sources date it differently. The British Annual Register records it under 12 October. According to The Times History of the War, the ministers of Russia, France and Great Britain asked for their passports as early as 5 October, when the Russian ultimatum expired, and left Sofia a few days later. The date of 13 October therefore marks the formal ending of relations by the government in London rather than the departure of the minister himself.

British warnings

Great Britain long clung to the hope that Bulgaria could at least be kept neutral. From July the British legation in Sofia had been headed by Hugh O’Beirne, until then counsellor of the British embassy in Petrograd, sent on a special mission in place of the minister, Henry Bax-Ironside, who had gone on leave. As the Foreign Secretary, Sir Edward Grey, later explained in the House of Commons, O’Beirne was introduced to Prime Minister Vasil Radoslavov on 8 July and presented his credentials to Tsar Ferdinand on 3 September, three days before the signing of the Bulgarian–German alliance.

After the announcement of Bulgarian mobilisation London began to put the matter more sharply. According to the memoirs of the French President, Raymond Poincaré, Grey declared to the Bulgarian minister in London that if Sofia did not give an assurance that the mobilisation was not directed against the Entente, the British minister would ask for his passports. When Russia came forward with its ultimatum on 4 October, the British government supported it. O’Beirne, however, did not hand over a note, but made an oral declaration to Radoslavov that Great Britain would break with Bulgaria if its mobilisation led to war in the Balkans.

War on the threshold

War came quickly. On 6 October Germany and Austria-Hungary attacked Serbia from the north, and on 11 October the first Bulgarian units crossed the Serbian border. According to the British official history of naval operations, London pressed its allies to declare war on Bulgaria immediately after Russia broke off relations. Agreement was slow in coming, however, because France was just then going through a government crisis. The British therefore broke off relations on their own, without waiting for a joint declaration.

In October the Bulgarian minister, Pancho Hadzhimishev, left London. The protection of Bulgarian interests in Great Britain was taken over by the Swedish minister. On 14 October Grey gave the House of Commons an account of the negotiations with Bulgaria and stated that, apart from Thrace, the Central Powers had offered Bulgaria more for mere neutrality than the Allies had promised or could honestly promise at the expense of her neighbours. That same day Bulgaria declared war on Serbia, and the next evening Great Britain declared that it was in a state of war with Bulgaria.