That's certainly how I use the rail network (and often the plane network - I've booked a flight from Europe to the far east with just a few hours notice on more

That's certainly how I use the rail network (and often the plane network - I've booked a flight from Europe to the far east with just a few hours notice on more than one occasion), and you can do that (unlike in europe where you have to book long distance trains in advance in many countries). I don't see the conceptual difference between going London - Paris or London - Edinburgh though?