The Germans attacked (22 April) ground which Smith-Dorrien had recently taken over from the French, using poison gas, causing some French units to break on the British flank. Sir John spurred on Smith-Dorrien in costly counterattacks, but thought the French had made "a horrible mistake" and "Joffre ... really deceived me" in holding the line so thinly. French was angry (26 April 1915) that French troops had broken under German gas attack, commenting that French troops had also failed to hold their positions in the retreat of 1914. Smith-Dorrien suggested withdrawing to the so-called "GHQ Line". French privately agreed, but was angered that the suggestion came from Smith-Dorrien. Plumer was the given responsibility for the Ypres Salient (27 April). Smith-Dorrien was finally relieved of command of Second Army (6 May).