Flag of Great Britain - one of the state symbols of the United Kingdom of Great Britain and Northern Ireland. Is a blue rectangular cloth with the image of a red cross in a white straight edging imposed on white and red oblique crosses.UK flag traces its history to 1603 , when King James VI of Scotland inherited the throne of England , and became King of England under the name of James I. In this case the union between England and Scotland had the character of a personal union , and they remained independent states. April 12, 1606 approved a new union flag States: for the Scottish flag of St. Andrew (white saltire on a blue background ) was imposed English flag of St George (red cross on a white background) .Flag , adopted April 12, 1606Originally the flag was used only at sea , both military and merchant ships of both countries. May 5, 1634 he was ordered to use only military courts as a jack ( hence its name The everyday " Union Jack » - «Jack» in English - bow flag ship or vessel ) , while merchant ships had to raise the flags of St. George ( English ) or St. Andrew ( Scottish ) . While ground forces continued to use flags of their countries. Scotland had some spread national flag variant , in which the white cross of St. Andrew was located over the red cross of the English .Following the adoption in 1707 of the Act of Union , which united the two kingdoms into a single Kingdom of Great Britain , united flag became the flag of the new state.In 1801, with the adoption of the Act on the union of Great Britain and Ireland was formed United Kingdom of Great Britain and Ireland. To flag that existed before, was added symbol of Ireland - St. Patrick's cross . In this white Scottish and Irish red cross intersect in a certain way . As such, the flag of Great Britain and has reached our days. Blue color modern Scottish flag lighter blue color used in the "Union Jack ." It should be noted that in Wales there are calls periodically put on the red dragon flag , national symbol of Wales, in order to avoid "discrimination" of this part of the United Kingdom .