This is a swallow-tailed red flag with a white cross overall. It is made of wool and cotton bunting, hand sewn with a rope halyard and wooden toggle attached for hoisting. The ensign is inscribed in ink on the hoist 'Adl. King C.B. no. 8'.

It belonged to the Duckworth-King family and relates to the collection of flags associated with Admiral Sir George St. Vincent Duckworth-King (1809-1891). George King was promoted to flag rank in 1862 and from Companion of the Bath (C.B.) to Knight Commander (K.C.B) in 1873.

The Dannebrog is often claimed as the oldest national flag in the world and dates from around the 13th century. The swallow-tailed version was reserved for the navy and royal institutions in 1625. The rectangular version is used as a national flag and civil ensign.