The current model is a complete dogs breakfast, but to see it as simply 'nationalised vs privatised' is nonsense, it is a mixed system with private operators operating franchises the government tenders out; we have simply done it very badly. There are examples of such systems working very well else where in the world, just as there are of truely nationalised and truely privatised systems working very well in others. Not having the rose-tinted view of BR that some seem to have, I have reached the conclusion that the British as a nation are just sh!t at running railways. Ergo, we should put the whole damn network out to tender to any private/public company or foreign government entity, provided they can demonstrate they already run a railway sucessfully elsewhere within certain service and efficiency parameters!
In a similar vain, we should also put the Germans in charge of our motorways...