how do we propose to protect what will soon become our MAJOR source of energy from enemy attack
We'll be in deep trouble power wise in any repeat of WW2, regardless of this vulnerability. Just compare:
In WW2 we generated all our electricity using coal we mined ourselves, so were self-sufficient 24/365.
Now our coal generation has been run right down and we no longer mine for it, importing all our coal.
We rely on around 10% of our current coming from French nuclear energy through cross channel cables.
We generate substantial quantities of current using natural gas imported from around the world.
We burn woodchip in some ex coal-burning stations, mainly using imported woodchip, or that grown on land we'll need for food in any future war.
Our nuclear power stations fleet has been run right down and in any case, we have to import the fuel.
And the rest from wind that might or might not be blowing when we need it.
Quite simply, we could not survive another WW2 as things stand at present.
.