Naval ensign of the Batavian Republic (1795-1806 pattern). It was captured by Admiral Sir Andrew Mitchell (1757-1806) during the Helder Expedition of 1799. The ensign is made of wool bunting with a linen hoist and is hand sewn. A rope and toggle is attached to hoist the ensign. Design: three horizontal stripes, red, white and blue. A white panel in the canton is painted with a figure of Liberty seated, holding a shield depicting the fasces in her right hand and in her left - a staff with a hat on top. The lion of the Netherlands supports the staff from the other side.

Frederick Augustus Duke of York commanded a Russo-British force in an invasion of the Netherlands in 1799, intended to reinstate the Prince of Orange. Admiral Adam Duncan commanded the fleet escorting the transports and the troops were able to land and occupy the Helder. Following a mutiny in the Dutch fleet which was anchored in an indefensible position, the Dutch admiral Storij surrendered to a squadron under Vice-Admiral Andrew Mitchell. A crushing defeat of the Anglo-Russian forces, obliged the Duke of York to evacuate them and Mitchell also had to withdraw from the Zuider Zee.

The flag was handed down through the family of Sir Andrew Mitchell.