The Guernsey flag was first flown in 1985 after years of investigation
Guernsey's flag is something everyone on the island is familiar with as it is flown from many buildings and the mast that stands on the weighbridge.
But until 1985 this was not the case as before then Guernsey used the cross of St George, the same as England.
The flag was adopted to mark the 40th anniversary of Guernsey's liberation from German Occupation during WWII.
As well as the red Cross of St George the flag also features the gold cross of William the Conqueror.
Bailiff of Guernsey, Sir Geoffrey Rowland, said: "It ties us back into our constitutional roots... here we are of Norman stock but linked indissolubly to the English crown."
The Guernsey flag flies outside the Royal Court everyday
One of the motivating reasons behind the creation of a flag for Guernsey was the confusion that was caused by using the same flag as England.
The example of this cited in the Guernsey Tourist Board's 1995 History of the Guernsey Flag was the Commonwealth Games where many competitors came away with the opinion that England was somehow fielding two teams.
The flag was designed, after much research, by the Guernsey Flag Investigation Committee chaired by the then Deputy Bailiff Sir Graham Dorey.
David Le Conte, who was secretary of the committee, said: "It was the end of a process that lasted maybe 100 years discussing what the Guernsey flag should be."
The Guernsey Ensign, flown from local ships, also features the gold cross
He explained that they "looked at many different designs" before settling on the one we know and added: "It's become an iconic symbol of Guernsey."
The flag became official as it was granted a Royal Warrant by Her Majesty The Queen and it was first flown on Liberation Day, 9 May 1985.
Culture and Leisure Minister, Mike O'Hara, said: "The population have really taken the flag to heart and its become part of our heritage."
Like the Guernsey flag, Sark and Alderney's banners also feature the Cross of St George with additions so all the flags of the Bailiwick follow a similar theme.
features the red cross with the island arms, a lion rearing on its hind legs, while the
was originally the standard of Dame Sibyl Hathaway and features a red canton with two yellow lions.