The document lists Blane’s achievements as Physician to The Prince Regent and the man in charge of the medical department of the British fleet during the American War of Independence.
Blane is credited with helping eradicate scurvy from the navy. He advocated the use of citrus juice as a preventative and introduced lemon juice as a daily addition to the naval diet in 1795.
The grant, in good original condition, is signed by the three Garter King of Arms with three seals present in painted japanned tin cases.
At Reeman Dansie in Colchester on March 9 it sold at £3300 (estimate £500-800), plus 20% buyer’s premium.