History

The Imperial Service Order was established by King Edward VII in 1902. It ceased to be awarded in the United Kingdom in 1993, although some Commonwealth nations, namely Papua New Guinea, continue to make nominations today.

The Order was awarded to members of the Civil Service in recognition of long and meritorious service in the United Kingdom and abroad. It was awarded for 25 years of service in the United Kingdom, 20 years of service in India, and 16 years of service in other tropical countries. These service requirements could be waived if it was awarded in recognition of particularly important acts of service. Women were first admitted to the Order in 1908.

Companions were entitled to use the post-nominal letters ISO.

There are a number of different versions that vary according to the royal cypher on the obverse. There are also different versions for men and women. Decorations for men feature a star behind the medallion, while decorations for women feature a laurel wreath behind the medallion. Men wear the decoration on a ribbon worn on the left breast, while women wear the decoration on a bow worn on the left shoulder.

There may be additional versions that differ in manufacturer or composition.