I think it'd help a lot if we took a big step back and did some real blue-sky thinking about the whole end-to-end transportation network.
Even though Britain is a small(ish) country, it has very diverse transport needs, and the current piecemeal approach doesn't begin to address them.
As far as freight goes, I think it's fair to say that a lot of it is bulk point-to-point stuff (or at least could be). To me, it's close to lunacy, for example, that a lorry should ever need to go anywhere near a seaport (I believe quite a lot of seaports think so, too - much of the capacity limitations in some of the busier ones is around fast access and turnaround by road). Then you only have to look at the amount of freight traffic heading up and down the M1 to see that there is lots of scope for concentration of that freight onto fixed links.
When we talk about the Beeching cuts, we often focus heavily on the effects on passenger traffic, but it's true of freight, too: because so many smaller towns no longer have rail connections, their essential goods are coming in on the back of large trucks which have probably driven a considerable distance to get there. Of course, you can't have a railway siding to the back of every TESCO (though, if that were given consideration when the locations are being planned, it's not inconceivable), but you can at least get the goods as near to their destination as possible before dropping a demountable wagon body onto the back of a (possibly electrically-powered?) truck for the last 10-15 miles.
We didn't have the logistical tools back in the 1950s to really run a kind of hierarchical freight network efficiently, but we do now: you could probably pretty well automate the entire train-marshalling business with current technology.
As for the passenger thing. Well, high-speed lines are sexy and look good when you're showing off to other countries, but I agree with what quite a lot of other people have already said on here: is it really what we need most of all? I still think we'd be better off reinstating a lot of our local feeder networks - perhaps as light rail, but for freight and passenger use - and, ideally, electrifying it, because almost all our renewable energy is going to be electricity. Maybe running it on tram-standard 750VDC would make the infrastructure cheaper? So, "downgrade" lots of the more distant parts of the network to light rail, but expand it. In my little corner of paradise (West Wales), we really do need something better than the three east-west links, but we're probably a special case. Obviously, you can't mix heavy and light rail traffic on the same tracks, so it would mean more interchanges. But, providing you were offering decent guaranteed connections, a reliable service to start with, and really good headways between trains even at the branch level, would that be too much to expect people to tolerate?
I'd be interested to hear from those who clearly know about such things what the implications (benefits and drawbacks) are for moving over to light rail for branch lines...
In rural areas, stations should be provided with more-than-adequate car parking, provided free of charge to rail users - perhaps with discounts for, eg, electric vehicles? - and/or really good, comprehensive bus/minibus/taxi linkups, since there will obviously still be quite large distances which aren't economic to cover by rail.
Once all this is done, you can start whacking motorists with all kinds of punitive taxes, road pricing, all that stuff, because you're offering them a credible alternative which should get them where they're going at less (or, at worst, the same) cost, just as fast, and hopefully just as painlessly.
Time for a paradigm shift, I think.