Light Cavalry, British. This trooper is probably from the 16th Light Dragoons (note the unit designation on the saddle blanket). Although this uniform is more likely to be from the Napoleonic wars, the 16th was one of only two light cavalry regiments who served in America during the Revolutionary War, the other being the 17th Light Dragoons
The Household Cavalry Mounted Regiment is comprised of The Life Guards and the Blues and Royals, two of the oldest Regiments in the British Army. They date back to the and have been the Sovereign's personal bodyguard ever since.