huge image of a snowcapped mountain covers the wall at the end of a long corridor of cells in Her Majesty’s Prison Berwyn, providing a glimmer of relief from the sterile landscape of indestructible concrete walls and wipe-clean floors, flooded with harsh white light.

What the polished PR images of the model £220m “super-prison” in Wrexham, north Wales, don’t convey is the constant echo of banging doors and shouting; the lack of ventilation, or the fact that the cell ceilings are so low you can press your hand flat against them. Nor do they show that Berwyn has some of the country’s highest rates of violence, weapon finds and “use of force” incidents by staff. Nor that the workshops still remain unfinished two years after the prison opened.

Originally planned to be one of the cheapest Category C jails to run in England and Wales, housing 2,100 men at £14,000 per year per place, HMP Berwyn is currently one of the most expensive, standing 40% empty and costing £36,000 per prisoner each year. It has been dubbed a “catastrophic failure”, yet it embodies the latest in prison thinking in the UK – which holds the title of the most incarcerated nation in western Europe. Recent analysis found the rate of imprisonment in England and Wales is about twice as high as Germany and roughly three times that of Italy and Spain. And it’s only set to rise.