Re: sort of reminds me
The issue is not the cut, but the lack of cross-provider connectivity.
97% of all UK provider networks interconnect is at the LINX. While it is now geographically distributed, it is still only around London.
In the event of a double cut, if the networks were interconnected elsewhere as well as the London area one could buy temporary transit and stitch its network via a tunnel for a couple of hours.
Unfortunately that is not the case.