If Scotland departs, remove the blue and the offcentre white X. Replace them with the Welsh White and Green, and perhaps the Cornish/Manx Black.

BTW, Cameron, the rest of the UK will NOT be desperately sad if Scotland departs. I'll be cheering at the loss of a hhuge economic drag. It comes to something when you have to go to that utter waster Brown to make your case, and says a lot about the utter incompetence of the political system.