....from the "Scottish Heritage" website.
EVERY nation needs a symbol to express its identity. Out of Scotland's history three core symbols emerged: a plant (the thistle, commemorating Alexander III's crucial victory against the Vikings at Largs in 1263), an animal (the Lion Rampant, remembering the Royal beast kept by King William the Lion) and a saint (Andrew, chosen to root Scotland in Bible values)....
....For Scots today Saint Andrew with his cross is still a potent symbol: Andrew was a networker who brought the wider world to meet his Master; the saltire is a multiplication sign of dynamism and enlargement. This recalls Andrew's initiative in bringing the boy to Jesus at the multiplication of the loaves and fishes and is an appropriate symbol of entrepreneurial skills for Scotland in the 21st century. There are other advantages: sharing Andrew as our patron with Russia and Greece gives Scots a worldwide orientation.
thanks to Flash for drawing my attention to this