In the short term more jails probably are the answer to overcrowding but in the long term we need to look at alternatives. Prison doesn't appear to act as much of a deterent to criminals, given the incidence of recidivism, probably because their life in the real world is no less miserable than behind bars. We need to bring real tangible economic and social improvement to these people, to make them think 'Actually life as a normal productive member of society is much better than being the wife of D-wing's tobacco baron'.

Isn’t the record prison population just the end result of years of ‘tough on crime’ rhetoric from our politicians? Clearly imprisonment hasn’t worked as an adequate deterrent. Worse, at great expense to the public I suspect it has nurtured an ever more hardened criminal sub-class in our midst. But it needs a far cleverer person than I to come up with a solution to this vicious cycle of crime and punishment.

If society decides that someone should be removed from that society for a period of time then that is exactly what should happen.
Every sentence should start with a third of it in solitary confinement, without the benefit of TV/radio or other privilege. If properly conducted, the next third should allow(reward) social integration and the final third, if the first two have been monitored sucessfully, should be re introduction to the outside community.
Solitory confinement would be the element of punishment which few would ever volunteer to repeat because there is no kudos in it and time is interminable if spent on one's own without social intercourse or entertainment.
This would allow sentences to be much shorter except for the most dangerous of prisoners. Five years, for example could become 18 months, thereby reducing the need for more prisons.
Resourses saved could, and should, be used to re introduce those who have served their term back into society and be helped to a far greater degree than is possible at present to avoid a repeat performance.

Friend of mine works in a prison and says life is so cushy inside that inmates see being locked up as a boring inconvenience rather than an actual punishment.

The trouble with prison is that is a deterrent only to decent law-abiding people who work for a living, pay their taxes and try to be of value to society. Hence judges jailing people for petty non-violent offences like not paying council tax in protest at the streets not being cleaned, for example. Politicians and judges KNOW that law-abiding people FEAR prison.

But a local violent offender who lives in a wreck of a flat and has nothing tangible to lose sees prison as no punishment.

The answer to cutting crime is sentences of mundane HARD WORK - AND LOTS OF IT. Criminals are essentially lazy and dislike being made to work or be bossed about. Three months breaking rubble for the roads is far more effective than three years smoking weed in some overcrowded Victorian jail.