Royal Standard of Scotland (the Lion Rampant flag)
The lion has been used as a heraldic device by the Kings of Scotland since William I of Scotland in the 12th century. The Rampant Lion appears to have been used first by Alexander II (1214-1249). The rampant lion stands erect, on it's hind legs, with it's head in profile and forelegs extended.
Traditionally, in Scotland, the Scottish Royal Standard is only used by Her Majesty the Queen in her capacity as Queen of Scots. However, outside of Scotland, this flag tends to be used as a second national flag.