Chamberlain was in charge of the war from his base in the Colonial Office. The Prime Minister rubber-stamped his decisions. Boer regular army units outnumbered the British 3:1 on the front lines and quickly besieged the towns of Ladysmith, Mafeking and Kimberley. Some ten thousand Cape Afrikaners joined the Boers. In mid-December 1899, during 'Black Week', the British Army suffered reverses at Stormberg, Magersfontein and Colenso. Chamberlain was critical privately of the British Army's military performance and was often vexed by the attitude of the War Office. When the Boers bombarded Ladysmith with Creusot ninety-four pounder siege guns, Chamberlain asked for the dispatch of comparable artillery to the war, but was exasperated by the Secretary of State for War, Lord Lansdowne's argument that such weapons required platforms that needed a year of preparation, even though the Boers operated their "Long Tom" without elaborate mountings. Chamberlain made a number of speeches to reassure the public, and worked to strengthen bonds between Britain and the self-governing colonies, gratefully receiving over 30,000 troops from Canada, Australia and New Zealand. The slogan "One Flag, One Queen, One Tongue" expressed their loyalty to the Empire, although they each had some Opposition to the Second Boer War. In particular, the contributions of mounted men from these settler colonies helped fill the British Army's shortfall of mounted infantry, vital in fighting the mobile Boers (who were an entirely mounted force of skilled marksmen).