My very honest scenario should have been, NO BRANCH LINES only through lines, creating circular routes, creating 2 paths to a destination not just one creating extra capacity but also providing a robust network when things go wrong, branch lines create a waste of resources and money! Imagine if the skegness route continued round the coast up via Grimsby and back towards Doncaster, or the Felixstowe route continued north via Ipswich and up towards Yarmouth/Norwich or most importantly if the Devon/Cornwall mainline had another route that didn't have to go via Dawlish, we all know that rising sea levels will eventually claim that line!
Portsmouth is an exception because its size, Liverpool is very much the same but circular routes work better in my opinion
Lines that shouldn't exist Isle of Sheppey to Sheerness, Marks Tey to Sudbury...I could continue!