Although the Ancient British Isles and Northern Europe coastline consisted of many different groups of people (Britons, Saxons, Vikings, Romans, Picts etc) the regions represented in the above flag are generally considered to have been overwhelmingly Celtic, although various historians dispute the extent, as this is alternative history, we don't have to worry about any of that. For the interest the regions represented in the above flag are from left to right: Brittany(France) Isle of Mann (UK) Scotland (UK) Ireland (Irish Tricolour in this case representing the island) Cornwall (UK) and Wales (UK). The trilogy/treskilion being used as an uniting symbol.
Given the fact that all of the regions (except Brittany) are in the British isles my first design was based on the Union Flag:
Like the Union Flag it is a combination of Crosses for the respective regions. The Crosses in the flag are St Patrick's Saltire (Ireland), St Andrew's Saltire (Scotland), Cross of St George (England, including Cornwall), Cross of St David (Wales) and Kroaz Du(Brittany). Unlike the Union Flag the saltires of Ireland and Scotland are on top of the other crosses as these nations are often regarded as the most Celtic. I also added the treskilion to the centre.
Given the fact that this flag has an awful lot to take in on it, and the fact it has to represent a union of six countries and the fact I forgot about the Isle of Man (I apologise to any Manx readers), I felt a different design was necessary.
This design is also based on a cross, the Celtic Crosses that were erected by early Christians throughout the British Isles (particularly Ireland and Scotland):
Again I have included a central treskilion. Their is no representation of any individual country of region, allowing the flag to be more flexible. The colours don't have any official meaning, but green and blue can be connected to Ireland and Scotland if the individual wishes. To see more designs visits the forum by clicking the link Here.