I cannot speak of the stupidity of Scotland breaking up the UK, but in my country, Quebec receives annually, over 10 billion in direct tax transfers, more than it pays; that is IN ADDITION to monies spent in Quebec by FedGovCan that are also spent in other Provinces. Quebec is a permanent ‘have-not’ Province and has been for more than 70 years, despite being the largest Province, with a wealth of hydro and mineral resources, it has the highest unemployment and welfare rolls AND by far, the highest paying welfare system in Canada.
Yet we STILL pay the separatist blackmailers each year, to remain in Canada! Why do the pols keep doing this? To keep Canada together. The majority of Canadians figure keeping Quebec in Confederation is worth it. Does that help to answer your question about why Westminster pols are keen to hang onto the Union with Scotland?
And BTW, I am of Scottish decent and have a soft spot for a country that I’ve never seen!