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.