National colours of the United Kingdom
The national colours of the United Kingdom are usually identified as the combination of red, white and blue in that order. These colours are the same as in the flag of the United Kingdom. The colours of the flag are in turn taken from the flags of England (white and red) and of Scotland (blue and white), which have been combined to form the union flag; to this was later added a red saltire for Ireland.
In maps of the 19th and 20th centuries, the territories of the British Empire were usually coloured red or pink. Historically, the British Armed Forces fought in red, a traditional colour that remains to this day in formal and ceremonial uniforms. Militarily, and in other contexts, the single chief colour associated with the UK is therefore red, such as in the famous British Army red coats.
In many international team sports the different countries of the United Kingdom are represented by separate teams. In those where the United Kingdom competes as one team, either under its own name or that of Great Britain (such as in the Olympic Games), colours used for the team are red, white and blue, where the blue is often a very dark blue. In motor racing, the national colour of the United Kingdom is green; the origin of this British racing green has its own, somewhat uncertain background.
At sea
At sea, 'national colours' refer to a distinctive flag used to demonstrate a vessel's country of origin. In 1867, an Order in Council defined that "the Red Ensign and Union Jack with a White Border continuing as at present the national colours for all British Ships". The white bordered Union Jack is commonly known today as the Pilot Jack.