It's the whole "too big to fail" argument that was played out with massive corporations in the 1980's and to a degree the first decade of this century.
Only this time it's being played out with the economy of a small semi-autonomous island.
The idea that the UK is going to bail us out is flawed. While the Government of Boris Johnson don't hate us in the same rabid manner as Corbyn did, they also owe us no favours at all.
It would be far easier to let us fail then install a replacement authority made in an image of their own liking.