Victory for the King..."Bayonet the whole"...
Fort Niagara was now vulnerable to any British attack. Its defenders consisted of a company of the 1st U.S. Artillery, another of the 24th U.S. Infantry, and other small detachments (mainly convalescent) from other regular units. The fort's commander was Captain Nathaniel Leonard, who had apparently been attracting unfavourable reports from his superiors since 1812 but had not been replaced. Although Major General Amos Hall of the New York militia was supposedly responsible for the defence of the frontier, practically no militia could be induced to turn out.
Drummond had ordered boats to be brought forward from Burlington. They proceeded by water to the mouth of the Four Mile Creek, from where Canadian militia carried them overland to Fort George. On the night of December 18, a force consisting of the grenadier company of the 1st battalion of the Royal Scots, the grenadier company of the 100th Foot and the two flank companies of the 41st Foot, with some small detachments of militia, crossed the river 3 miles (5 km) above Fort Niagara. The force numbered 562 and was under the command of Lieutenant Colonel John Murray, the commanding officer of the 100th Foot. They were equipped with scaling ladders and under orders to use the bayonet so as not to lose the advantage of surprise.
They captured an American picket, which had been trying to stay warm rather than keep watch. From one of the prisoners, they learned the American challenge and password. They then approached the fort. A party under a sergeant led them to the gate, where they were challenged by the sentry. They gave the correct password and got through the outer gate. They got through the inner gate the same way, before the sentry there raised the alarm. It was too late to stop the British rushing in.
The defenders barricaded themselves inside the south redoubt of the fort and held off repeated attempts to break into the building. However, after they refused to give up, the British offered no quarter to the defenders. Upon breaking into the building the infamous order of "Bayonet the whole" was given.
The defenders suffered 65 killed. 344 prisoners were taken, of whom 14 were wounded. (This is larger than the supposed number of defenders. Presumably, some militia were sleeping in the fort or were rounded up outside). Captain Leonard was captured at his home, several miles away. Only six attackers were killed (with 5 wounded).
A force consisting of the battalion companies of the Royal Scots and the 41st under Major General Phineas Riall followed Murray's troops across the river and proceeded to burn almost every village on the American side of the river, in reprisal for the burning of Newark. Some Indians accompanied Riall, and several American settlers were scalped. Riall was eventually halted by some militia who destroyed the bridge over Tonawanda Creek.
A few days later, on December 30, Riall crossed the river higher up, and proceeded to repeat the destruction at Buffalo and Black Rock. Here however, the navy yard was a legitimate target. Four armed schooners and brigs were destroyed. Practically no American militia turned out to defend their homes.
Fort Niagara remained in British hands for the rest of the war.