In the southern portion of the line the 151st Brigade of Durhams had been slowly forced back from the Lestrem sector until they were on the line of the Lys, which they reached in the evening of April 10. At that date the 150th Yorkshire Brigade was still firm upon the river, but the left-hand battalion, the 5th Yorks, had thrown back its flank, since the enemy, brushing aside the right wing of the Fortieth Division, had crossed the stream and turned the Fiftieth from the north. The Fortieth was still fighting hard, as already described, and endeavouring to hold back the attack, so that the German advance was slow. Early in the morning of April 11 the attack became very severe, and broke through to the west of Estaires--the river at this point runs from west to east--driving back the Durham Brigade, which was absolutely exhausted after forty-eight hours of ceaseless fighting without assistance. Their resistance had been an extraordinarily fine one, but there comes a limit to human powers. The whole division was at the last extremity, but fortunately at 12 o'clock on the 11th, two brigades of the Twenty-ninth Division (Cayley) came up in relief. {244} So close was the fighting, however, and so desperate the situation, that General Riddell of the 149th Northumberland Fusiliers Brigade refused to disengage his men from the battle, since the confusion of a relief might have led to disaster. He was at the time holding the line astride the Meteren Becque, north of Estaires, covering about 1000 yards of vital ground. Here the Germans attacked all day, making prodigious efforts to push the 4th and 5th Northumberland Fusiliers out of Trou Bayard. The ground between this point and Pont Levis, the bridge at the east end of Estaires, was dead flat, and afforded no particle of cover. Fifteen British machine-guns stationed beside the infantry swept all this expanse, and cut down each wave of attack. Four times the place was supposed to have fallen, and four times the Germans fell back, leaving long grey swathes of their dead. It was not until 3 P.M. that the stubborn Northumbrians found that their right was completely exposed, and were forced to retire from a position which they had sold at a terrible price.