Formally introduced in 1992 by the then Scottish Secretary Ian Lang, GERS was deliberately designed – as the minister acknowledged in a leaked document – to “undermine” the UK government’s rivals. Its conception was intended to demonstrate to the public that devolved self-government was A Bad Thing.
itisintruthnotforglory 
In a nutshell … but if you want more exposition go over to our friend WGD here :
https://weegingerdug.wordpress.com/2018/08/22/the-scottish-version-of-groundhog-day/
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