The United Kingdom is a place of curious tradition. Beyond the formalities of queens, dukes, and baby princes, they also have a parliamentary flags and heraldry committee which has been very busy lately. Since Scotland may be leaving the United Kingdom this Thursday, Lord West, the deputy chairman of the committee, has said it would be "nonsense" to keep Scotland's color (blue) in the Union Jack flag. West told The Daily Mail, "In the event of a 'Yes' vote I cannot see how you can save the flag of the United Kingdom."
The Union Jack is a combination of some other very historical flags. It started off as St. George's red cross flag in 1270. In 1606, it was combined with the cross saltire of St. Andrew, the Patron Saint of Scotland. That's the white cross on the blue background Lord West is not fond of right now. After that, St. Patrick, the Patron Saint of Ireland, had his cross saltire incorporated into the flag. That's the red diagonal. On the first day of 1801, the Union Jack flag as we know it today was created.
While that is when the flag came to be, it was never actually formally adopted. Chief executive of the Flag Institute Charles Ashburner told The Guardian that the Union Jack "fell into use" and therefore "nobody controls the union flag." He also notes that removing the blue would allow for Wales to be represented in the Union Jack. Wales could also be represented using the flag of their Patron Saint David, a black and yellow cross.