Simon Jenkins: If the Scots can get tax-raising powers so should London

If Scotland votes yes, does it matter to London? The answer is of course not. London can take it. There may be 300,000 Scottish expats in the capital, making it the third-largest “Scottish” city anywhere, but we welcome “foreigners” from any and every land. There are even more French and Americans. The “end of the Union” means nothing in particular to london but we can certainly deride the incompetence of Westminster’s political elite for letting Scotland go, as it let Ireland go in the 1920s. London’s Irish survived and prospered, so would London’s Scottish.

The truth is that Scotland after an independence negotiation would not really “go”. Deals would be done such that, for ordinary people, life would be much as before, north and south of the border. Political pride might be hurt but such pride comes before a yawn.

So why is Boris Johnson against not just Scottish independence – he calls it a sleepwalk to tragedy – but declares himself outraged by “further devolution”? The answer of course is that he wants to lead a Conservative “and Unionist” party. Everything he says must now be seen through that prism. Since seeking a Commons seat, his priorities have shifted. In politics you cannot sleep with two mistresses, London and Parliament, and the Mayor has chosen the latter.

But Johnson has a cannier argument on Scotland with which I totally agree. Scotland is now being offered “further devolution” to stay in union with England. Why, asks the Mayor, should five million Scots be offered tax-raising powers and budgetary freedom to stay in the union when Londoners have none? As he put it last month: “What has England ever got out of this devolution process? If you want to have growth in English cities, then you should do what Manchester wants, what Liverpool, Leeds, all of us want — and that’s give us more tax-raising powers.”

That is hardly a reason against devolving taxes to Scotland but it is a reason for devolving them within England. And while Manchester, Liverpool and Leeds have been useless at winning such devolution — led by politically inert local parties — that is not true of London. Johnson is an elected mayor with clout. Indeed, he may never have more clout than now, when his star is in the ascendant.

The United Kingdom is currently in the grip of constitutional panic. Even after thousands of Scots have voted by post in their independence referendum, David Cameron, Nick Clegg and Ed Miliband are hurling bribes northwards to secure a No vote. For six months they threatened Scotland with fire, plague and the sword under “project fear”. They “warned” the Scots that their pensions and benefits would go, their borders would be manned, their defences would collapse and terrorists would proliferate.

Now all is love-bombing, sweetness and light. The Scots can have all the money and power they want, if they will promise to love England. Subsidies will flow. Above all, the Scots will be offered unspecified extra powers. Edinburgh can even fix its own income tax and — who knows? — perhaps its corporation tax and other imposts. If I were the Scots I would not trust a word of it. I recall the Arab warrior who invited his enemies to a peace banquet and then roasted them on a spit.