In November, 1775, the Governor of the Crown Colony of Virginia (John Murray, Earl of Dunmore) issued a proclamation that, in order to defeat "treasonable purposes", he was declaring that a state of martial law existed in Virginia, and those colonists that refused to "resort to His Majesty's standard" would be traitors.
With only 300 soldiers, seamen and loyalist recruits in the entire colony, Dunmore had an urgent need for manpower - and no help could be expected from British Headquarters in Boston.
Hundreds of newly-freed slaves joined Dunmore, who created the Ethiopian Regiment. At a skirmish at Kemp's Landing, one ex-slave had the pleasure of capturing his old master and bringing him into the British lines. The first, and only, major action involving the Ethiopian Regiment was at Great Bridge. Here, Dunmore's force of 600 troops (nearly half ex-slaves, together with companies of the 14th Regiment of Foot) were repulsed with 61 casualties.
It has been estimated that of the 800 or so slaves that joined Dunmore, 100 of them had come with their loyalist owners.
As well as troops, blacks were utilised by Dunmore as pilots on the Chesapeake, and its associated waterways, as foraging parties, and on garrison duties at Gwynn's Island.
Smallpox began taking a toll of his forces, primarily among these ex-slaves. By June, 1776, he had about 150 effective men, even though 6 or more joined him daily. In August, 1776, the healthiest 300 went with Dunmore to New York, and further military service
Dunmore's ex-slaves were not the only blacks to join the British forces. Free blacks were as able to decide their future as well as any free white, and many were loyal to the British government. It was said at the time, that the belief that a British victory would bring freedom was almost universal in slave society. Tens of thousands fled to the British, and although no general campaign was undertaken to enlist black soldiers, those who sought British protection were received.
[According to Jefferson, 30,000 Virginia slaves fled to the British. 25,000 (two-thirds) of the slaves in South Carolina joined them in the latter part of the war, as did three-quarters of the slaves in Georgia. These people were aware that liberty was, for them, unattainable under an American government. Compare this with the better publicised 5,000 who joined the patriot cause, some of whom were "stand-ins" for their masters, who preferred to avoid military service.]
A large number of these black troops were pioneers, with three or four assigned to each regiment. The Engineer Corps had many duties requiring skilled labour - constructing batteries, opening trenches, repairing lines. The Royal Artillery received many carpenters, wheelers, smiths, sawyers and turnwheels. Those with the appropriate skills were orderlies in hospitals, pilots on waterways, or crew on the many privateering barges used for foraging and collecting refugees.
There were also a number of spies and informers, and those with local knowledge acted as guides to couriers and military forces.
Unskilled labourers were employed in public works, duties such as digging latrines, cleaning the streets, and as officers' servants.
At the end of the war 80,000 to 100,000 blacks evacuated with the British , most going to Jamaica, Nova Scotia, and to a new country on the west coast of Africa - Sierra Leone.
Further Reading:
The Negro in the American Revolution by Benjamin Quarles
The British Soldier in America by Sylvia Frey
Water from the Rock: Black Resistance in a Revolutionary Age by Sylvia
Frey