First used by British at the Somme 1916 with poor effect as they were sent in alone so the progress they made was lost without the soldiers already there to continue the push. Tanks suffered from mechanical failures, were too slow (around 2mph) and cumbersome, were used independently of artillery and infantry and were too few in number (just 49). By Cambrai 1917 over 450 tanks were used en masse as part of a coordinated Allied assault alongside infantry and artillery. Helped to restore mobility to the battlefield.