Where does come from?
Versions of the Union Jack flag have been flown over all or some part of the British Empire, British Isles, or United Kingdom since 1606. Today, the Union Jack is the official flag of the United Kingdom, which includes England and Wales, Scotland, and Northern Ireland.
The flag for the United Kingdom emoji was added as part of Emoji 1.0 in 2015 based on Unicode’s earlier, two-letter country codes. The two-letter code for flag for the United Kingdom emoji is GB (Great Britain), which is how the emoji will display on unsupported platforms.
While officially called United Kingdom, the emoji commonly goes by Union Jack, UK flag, (flag for) Great Britain, or British flag. Under the 2017 release of Emoji 5.0, different flag emoji were created for England (🏴), Scotland (🏴), and Wales (🏴). Northern Ireland flies the Union Jack.
Who uses ?
In text messages and social media, people use the Flag for United Kingdom to stand for the UK collectively. Some posts may altogether substitute the flag for the terms UK or United Kingdom. Common themes for use of the Flag for the United Kingdom include sports, politics, travel, language, and pop culture, often marking national pride (e.g., Go Team GB at the Olympics 🇬🇧!).
Some social-media users also include the Flag for the United Kingdom emoji in their usernames to indicate that they hail from the United Kingdom or that their account shares news about a UK-related topic. The flag for the United Kingdom emoji may sometimes accompany topics concerning British Commonwealth countries, such as Australia, Canada, and India, due to their historical ties.
Websites offering English-language content may use the Flag for the United Kingdom emoji to indicate they offer content in English. The emoji may more generally stand for British English.
Be mindful that confusing the flag for the United Kingdom for the individual flags (or countries) of Wales and Scotland may offend people who live or are from there, given the history of the British Empire.