Perhaps Scotland could get full autonomy over its own finances. Essentially, give the Scots everything they want except full independence.

And perhaps Britain could move to a fully federal system, meaning some form of English Parliament; senior Tories like Boris Johnson have said they are open to federalism.

Does that radical or dramatic? Yes, but these are extraordinary times: the most dramatic changes in the British constitution must surely be considered to avoid an even more dramatic and destructive outcome: Scottish independence.

And even if those dramatic measures are taken, there is no certainty of success. The breakup of Britain must now be considered a realistic possibility.