You can fly the Union Flag every single day of the year if you like. No permission needed. But if you want to join the official fun, government buildings fly it on key dates: the King’s birthday, Commonwealth Day, Remembrance Sunday... You get the idea.
Here’s a cheeky tip: don’t fly it at night unless it’s lit up. Otherwise, it’s like wearing sunglasses indoors. Not illegal, just a bit mysterious. And if there’s a storm? Take it down. A soggy flag is a sad flag.
Correct Way To Fly Union Jack Flag at Spencer Ebert blog
The “St George’s Cross” Confusion (We’ve All Been There)
Please, for the love of loyalty, don’t call the Union Flag “the English flag.” That’s St George’s Cross—a simple red cross on a white background. The Union Flag represents the whole United Kingdom (England, Scotland, Northern Ireland, and Wales, though Wales sneaks in via England’s cross).
If you fly only the St George’s Cross, you’re being very English. Fine! But if you want to represent everyone—cousins, in-laws, and that one Welsh friend who’s always correcting you—go full Union Flag.
