The French fleet was expected to arrive shortly, and the Irish, reinforced with men, arms, and supplies of every kind, would probably resume the offensive during the winter, and he would find himself cut off from all supplies and assistance.  He determined, therefore, to make one more effort before retiring.

He had, throughout the siege, been in communication with several Irish officers of high rank, and especially with General Clifford, who commanded the cavalry posted on the river opposite to his camp.  These officers were as desirous as he was of bringing the war to an end, for they foresaw that if, after the arrival of the French, they succeeded in driving the English out of the country, Ireland would simply become a dependency of France, and they preferred the English connection to this.  Ginckle determined to try, again, the same feint which had succeeded at Athlone.  The workmen were kept busy repairing the works at Kilmallock, and preparing that place for the reception of the army.  The greater portion of the baggage, and a regiment of Danes, were sent forward to that town.  The batteries ceased firing, and the cannon were dismounted at several points, and the Irish were persuaded that the siege was about to be abandoned.

Meanwhile, Ginckle was busy collecting boats, and preparing a bridge across to a small island, which lay not far from the Clare side of the river.  On a dark night, the boats were brought up and the bridge constructed, and, led by six hundred grenadiers, a strong force of infantry, cavalry, and artillery crossed to the island, and then waded through the shallow water beyond to the mainland.

A few men, posted on the island, carried the news to Clifford, but he gave no orders to the four regiments of cavalry and two of infantry under his command, nor did he send any notice to the camp.  Some of the infantry and cavalry, however, ran without orders to the bank, and kept the grenadiers in check until the British cavalry had crossed, and compelled them to fall back.  The British cavalry then dashed forward to the Irish cavalry camp, which they took completely by surprise.  Panic stricken at this unexpected attack, the soldiers and the citizens in the town camp fled in all directions, and, great numbers rushing to Thomond Bridge, entered the city by that narrow approach.

Had Ginckle at once pushed forward, he would have captured almost the whole of the Irish officials and civilians on the Clare side of the river; but, fearing an ambuscade, he halted his troops before advancing to the Irish camp, and this gave time for most of them to escape.  Being afraid that the garrison would sally out from the town, and attack his lines on the other side of the river, he recrossed the Shannon with his troops, carrying with them a crowd of civilians, among them a number of persons of rank, and officials with the records and public treasure.

The confusion and surprise in the town were so great that the Irish generals took no steps whatever, either to hinder his passage back across the river, or to attack either portion of his divided army.  They knew that treachery must have been at work, to have enabled the enemy to surprise the camp, and, as they could not tell how far that treachery extended, they abstained from all action.