The flag is only known as a Union Jack, when it is flown off the Jack-Staff of a British Ship. When it flies above a building, say Parliament, for example, it's known as the Union Flag or simply the National Flag.
Actually, as of 2013, that is wrong. Graham Bartram, a British vexillologist who is the secretary-general for congresses of the Fédération internationale des associations vexillologiques and the chief vexillologist of the Flag Institute, when interviewed on the BBC Broadcasting House programme on 13 October 2013, stated that either name was perfectly valid whatever the purpose. He stated that the theory that the flag should only be referred to as "Union Jack" when flown at sea was wrong.
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I have no intention whatsoever to start placing the Union Jack, the St George's Cross, British currency notes on the website. *insert angelic emoji here*
Thanks all!
