This plaque of a lion holding a sword in its raised paw is the symbol of the Kingdom of Kandy, the kingdom based in central Sri Lanka (Ceylon), and was used on royal standards and to denote the King’s property.
It has been cut somewhat roughly from a thin piece of brass.
See a related example in the British Museum.
The Kingdom of Kandy was an independent kingdom of the island of Sri Lanka, located in the central and eastern part of the island. It was founded in the late 15th century and lasted until British occupation in the early 19th century.
This plaque is from the collection of Sir Christopher Ondaatje. Ondaatje is of Sinhalese and Dutch ancestry and was born in Sri Lanka (or Ceylon as it was known) in 1933. A businessman, writer and Olympian, he is the older brother of author Michael Ondaatje, author of The English Patient, among many works.
This actual item is illustrated in the book on the Ondaatje Collection (Weereratne, 1999, p. 156).
Weereratne, N., Visions of an Island: Rare works from Sri Lanka in the Christopher Ondaatje Collection, Harper Collins, 1999.