Government Service Ensign
Defaced Blue Ensign flown by British vessels / From Wikipedia, the free encyclopedia
The Government Service Ensign is a defaced Blue Ensign flown by vessels owned by the British Ministry of Defence for which no other ensign is appropriate.[1] It is most commonly seen flown by warships undergoing contractors' trials before being commissioned into the Royal Navy, and former Royal Maritime Auxiliary Service vessels now operated by Serco Denholm.[2]
The Government Service Jack is a square flag of similar design.[3]