General Howe had made good use of his time on Long Island. The eventual British attack was carefully planned and gained the success it deserved. On the evening of 26 August the main force moved east towards Jamaica Pass, using back roads to avoid being detected. General Henry Clinton led the van, Lord Cornwallis the reserve and General Percy with Howe the main army. At three in the morning on 27 August the British surprised and captured the five American guards at the Jamaica Pass and without any difficulty were behind the American lines.
They now began a quiet march towards Brooklyn, hoping to trap the American forces on the rest of the Heights of Guan. They were aided in this by two diversionary attacks, both also launched at about three in the morning. On the American right, where the Heights reached the coast, General James Grant launched a diversionary attack, which convinced the commander of the American right, William Alexander, ‘lord’ Stirling (his claim to the title had been rejected) that the main attack was about to come. Further along the line, the Hessians bombarded Sullivan’s forces, pinning them down half way along the Heights.
The main assault began at nine in the morning. The main British force reached Bedford village, behind Sullivan’s position, and opened fire. The Hessians also attacked up the pass and Sullivan’s command collapsed. The main American resistance came from Stirling on the American right. His Maryland and Delaware Continentals had only arrived on Long Island on the previous day, but fought doggedly for two hours. Reinforced by units from Connecticut and Pennsylvania, Stirling held on until he was almost surrounded. Finally, he ordered a retreat and the bulk of his men escaped across the marshes around Gowanus Bay, remaining behind with a rearguard of to 250 Marylanders to cover the withdrawal.
By noon, Howe’s men had captured the Heights of Guan, and forced the Americans in disarray back into their positions around Brooklyn village. The Americans were now very vulnerable, and Howe’s men were keen to finish them off, but once again Howe held back. 28 August saw Washington send three more regiments into Brooklyn, while Howe began to build regular siege works. Bad weather prevented the British from blockading the Brooklyn position from the sea, but also gave them the idea opportunity to use their superiority with the bayonet against the demoralized and outnumbered Americans. Once again, Howe declined to push his advantage, and finally on 29 August Washington came to realize that his position on Long Island was untenable. That night the 9500 American soldiers apparently trapped at Brooklyn were evacuated by sea to Manhattan Island.