On Tuesday 28 July, exactly one month after the assassination of the Archduke Franz Ferdinand, Austria declared war on Serbia. At 4.15 pm the Foreign Office received a telegram from Dayrell Crackanthorpe, Britain’s Chargé d’Affaires in Belgrade. The Austrian Minister had left the city and an immediate attack was expected.
At 7.20 pm, a further telegram from Sir Maurice de Bunsen, the British Ambassador in Vienna, confirmed that war would be declared that day. Later, Austrian artillery began shelling Belgrade across the Danube and negotiations with Russia fell apart.