"The current United Kingdom dates from 1603 with accession of James VI to the English throne"

Simply not true though! Betweeen 1603 and 1707 (Cromwellian interlude aside when they were temporarily united by the annexation of Scotland by the English Republic)the two seperate kingdoms of England and Scotland remained. They simply shared a monarch in a similar way to the modern UK, Austraila and Canada etc do. It was a personal regal union of two seperate kingdoms rather than the creation of a united kingdom. The United Kingdom of Great Britain was created by the 1707 Treaty of Union. Below is article 1 of the treaty as ratified by the Scottish parliament.


I.       THAT the two Kingdoms of Scotland and England shall upon the first day of May next ensuing the date hereof, and for ever after, be united into One Kingdom by the Name of GREAT BRITAIN; And that the Ensigns Armorial of the said United Kingdom be such as Her Majesty shall appoint,, and the Crosses of St Andrew and St George be conjoined, in such manner as Her Majesty shall think fit, and used in all Flags, Banners, Standards and Ensigns, both at Sea and Land.