Iceland's first national flag was a white cross on a deep blue background. It was first shown in parade in 1897. The modern flag dates from 1915, when a red cross was inserted into the white cross of the original flag. This cross represents Christianity. It was adopted and became the national flag when Iceland gained independence from Denmark in 1918. For the Icelandic people the flag's colouring represents a vision of their country's landscape. The colours stand for 3 of the elements that make up the island. Red is the fire produced by the island's volcanoes, white recalls the ice and snow that covers Iceland, and blue is for mountains in the distance. The state flag (Tjúgufáni) differs from the civil one, that the outer rectangles are three times longer than the hoist side rectangles and split at the end, cut directly from the outer corners to its centre line. Cutting the inner edges of the outer rectangles at 4/7 of outer length and 3/7 of inner length of the outer rectangles. When this cut encounters the edge of the red cross it is cut vertically.

The flag of Lithuania consists of a horizontal tricolor of yellow, green and red. It was re-adopted on March 20, 1989, almost two years before the re-establishment of Lithuania's independence and more than three years before the collapse of the Soviet Union. It was first used in Lithuania's first period of independence (in the 20th century) from 1918–1940, which ceased with the occupation first by Soviet Russia and Lithuania's illegal annexation into the Soviet Union, and then by Nazi Germany (1941–44). During the post-WW2 Soviet occupation, from 1945 until 1989, the Soviet Lithuanian flag consisted first of a generic red Soviet flag with the name of the republic, then changed to the red flag with white and green bars at the bottom. The last alteration to the current flag occurred in 2004 when the aspect ratio changed from 1:2 to 3:5. The flag is identical to the flag of the Danish island Ærø, also located by the Baltic Sea, and to that of the Colombian department of Bolívar. It is also similar to the flag of Myanmar.

Northern Ireland has not had its own unique, government-sanctioned flag since the Northern Ireland parliament and government were prorogued in 1972, and abolished in 1973.[1] During official events, the British government uses the Union Flag, which is the official flag of the United Kingdom of Great Britain and Northern Ireland, and is the only flag used by the government in Northern Ireland.[2] The Saint Patrick's Saltire is sometimes used by the government to represent Northern Ireland alongside the other countries of the United Kingdom, and is the centrepiece of the badge of the Police Service of Northern Ireland. The Ulster Banner remains in use by unionists, a number of sporting organisations in Northern Ireland and some local government authorities under Unionist control.

There was a claim that the red cross worn as an emblem was brought to England as early as the 1190s by Richard the Lionheart, but this cannot be substantiated.[8] The red cross was introduced to England by the late 13th century, but not as a flag, and not at the time associated with Saint George. It was worn by English soldiers as an identification from the early years of the reign of Edward I (1270s), and perhaps originated a few years earlier, in the Second Barons' War (specifically in the Battle of Evesham of 1265, during which, according to chronicler William Rishanger, Simon de Montford observed that the king had taken from him the idea of having his soldiers marked with a cross). Saint George rose to the position of "patron saint of England" in a process beginning in 1348 with the foundation of the Order of the Garter and culminating with the abolition of all saint's banners except for the St George's banner in 1552. From 1348 and throughout the 15th century, the St George's Cross was shown in the hoist of the Royal Standards of the Plantagenet kings of England.

The flag of the Faroe Islands is an offset cross, which represents Christianity; following, as with other Nordic flags, the tradition set by Dannebrog. The flag is called Merkið, which means "the banner" or "the mark". It resembles the flags of neighbouring Norway and Iceland.