There isn't an official pan-Celtic, but two flags are most commonly used. This is the most popular:
This flag is made with the amalgamation of flags of seven Celtic nations, from top left, in clockwise direction: Galicia, Ireland (in this case, not only the Republic of Ireland, but in a pan-Irish context), Scotland, Cornwall, Isle of Man, Wales and Brittany. Other common variant have only the six original celtic nations, removing Galicia. In the center, a triskelion, a motif common in celtic art.
The other one is a proposal by Robert Berthelier in the 1950s:
This flag have green and golden yellow colors, commonly associated with the Celts, and two conjoined triskelions (in the style of a celtic knot), representing three Gaelic peoples - Scot, Irish and Manx - and three Brittonic peoples - Welsh, Cornish and Breton.
The sketch that I had (as said in first paragraph) is heavily influenced by Andrew Boada's amazing "Irish Celtic Cross". Here is it:
This flag has the same colors of the Berthelier's proposal, with the addition of white. It represents a Celtic cross, but touching the borders instead of square as the latter is used by Neo-Nazis. I like how this flag is simple and vivid. But, to avoid any misconception, I made the reference to celtic flag much more subtle on my next proposal:
It's very much like the anterior flag, with the exception that a white triskelion was added on the center of the flag.
As you can see, the designs don't have any very original approach, but I think them may work well.
Your comments are always welcome.
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