If you do London->Edinburgh by train now, then assuming you're willing to book to a specific train and book a couple of months in advance (which is probably wha

If you do London->Edinburgh by train now, then assuming you're willing to book to a specific train and book a couple of months in advance (which is probably what you were doing with your plane ticket) then you can get a ticket for 50 or 60 quid each way, total time of about 4 and a half hours. Of course if you're starting a little further north (say, Cambridge), then the train is cheaper still. Plus you have to allow for the cost of getting from where you start to the airport if you're flying. So the economic argument has tilted considerably since your experience of two decades past (though the plane still wins if time-elapsed is your primary requirement). Personally I take the train for this journey -- last time I did Cambridge to Edinburgh I paid less than 30 quid for the outbound leg and not much more for the return. And you can get decent prices for first class if you want a little bit more luxury at way less of a premium than the airlines will charge you for that...