英国国旗产生于1801年，是由原英格兰的白地红色正十旗(代表英格兰守护神圣乔治)、苏格兰的蓝地白色交叉十字旗(代表苏格兰守护神圣安德鲁)和爱尔兰的白地红色交叉十字旗(代表爱尔兰守护神圣帕特里克)重叠而成。

　　按照顺序，首先是苏格兰旗(St Andrews’s Cross)和英格兰的旗(St George’s Cross)组合在一起，然后爱尔兰王国的旗帜(St Patrick’s Cross)也被叠加了上来，最后形成的了现在的样子。

　　Saint Andrew's(圣安德鲁)Cross是苏格兰的国旗，象征着苏格兰国民的忠诚。圣安德鲁是苏格兰的守护者，传说他就是被钉在X型的十字架上，所以知道为什么旗子上是个白色X型的十字啦!

　　请看下面介绍：

　　The Union Flag has been used in a variety of forms since the proclamation by Orders in Council (枢密令) 1606, when the Flag of Scotland and the Flag of England were first merged to symbolize the Union of the Crowns. (The Union of the Crowns having occurred in 1603).

　　In Scotland, and in particular on Scottish vessels at sea, historical evidence suggests that a separate design of Union Flag was flown to that used in England. However, following the Acts of Union 《合并法令》of 1707, which united the Kingdom of Scotland and the Kingdom of England to become the Kingdom of Great Britain , the 'English' version of the Union Flag was adopted as the official Flag of Great Britain.

　　From 1801, in order to symbolise the union of the Kingdom of Great Britain with the Kingdom of Ireland, a new design which included the St Patrick's Cross was adopted for the flag of the United Kingdom of Great Britain and Ireland. The Flag of the United Kingdom, having remained unchanged following the partition of Ireland in 1921 and creation of the Irish Free State and Northern Ireland, continues to be used as the flag of the United Kingdom of Great Britain and Northern Ireland.

　　1606年，詹姆斯一世统一英格兰和苏格兰时，将这两面旗帜图案重叠起来，作为大不列颠的国旗。英国国旗的历史最早可追溯到1606年。1603年，当时英格兰和苏格兰拥有了同一位国王，在英格兰的名叫詹姆士一世，在苏格兰的名叫詹姆士六世。

　　1606年4月12日制定的国旗，是由英格兰的圣乔治十字旗和苏格兰的圣安德鲁旗交叉合并而成，但和现在的有点不一样，没有红色的斜杠(圣帕特里克十字)。

　　爱尔兰的圣帕特里克的白地红色“x"型十字旗，最早是爱尔兰菲茨诺德家族的旗帜;1801年，爱尔兰与大不列颠联合组成王国后，这面旗帜又与大不列颠国旗重叠，最后形成了大不列颠及北爱尔兰联合王国的这面构图奇特的“米字旗”。