United Kingdom 5th Royal Veteran Battalion.

U.K. 5th Royal Veteran's Reserve Regiment circa 1812, deaccessed from the Smithsonian.
This post 1801 British Infantry Color can be distinguished from its predecessors by the diagonal, so-called St. Patrick's red counter-changed cross in the canton. Used between 1802 and 1819, carried by the 5th Royal Veteran Battalion.

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