A course of action that affects West of Scotland, Carlisle and Preston signalling centres would give a good number of miles from Scotland to Preston and South of Preston. Effectively closing the West Coast Main Line. Noises have already been made about Avanti services. So the sleeper would be no better.
Similar noises have also been made about LNER services. So no alternative for the sleeper on the East Coast. That would effectively be the Edinburgh and Tyne signalling centres.
Guess we need to wait and see what is affected, but the outcome does not look good.