Locked in: this former prison has been relaunched as a five-star hotel

Floating in a candlelit subterranean swimming pool, staring up through a glass ceiling at the stern Victorian architecture of Melbourne's former Pentridge prison, is a close approximation of an out-of-body experience. It's at once gloriously serene and heavy with the weight of history. Centuries grind against each other like tectonic plates.

At the Interlude, as the boutique hotel inside the former HMS Prison Pentridge is known, you won't get a room with a view.

Each suite, wonderfully plush as it is, has only a series of small, barred windows set high in the bluestone walls. Their tantalising snatch of sky was the only glimpse of the outside world seen by the inmates over the prison's 150-year history, from colonial bushrangers like Ned Kelly to contemporary criminals such as Chopper Read.

Stepping inside the neo-Gothic grey walls in the hip inner-northern suburb of Coburg, 20 minutes' drive from the CBD, is no longer a form of punishment. Quite the opposite. But to simply call Interlude a luxe hotel is to miss the point. Opened in July after a masterful renovation of the former B Division (once home to long-term prisoners and those with behavioural problems, no less), it's a stay with a difference.

Part of a global trend of turning superannuated prisons into hotels, the Interlude is upcycling at its most ambitious.

Tellingly, Pentridge took two years to build in the mid-1800s; its reinvention into an upscale experiential hotel took seven years of painstaking building works under the guidance of heritage experts. Its 19 suites each comprise five former cells turned into luxe digs with marble bathrooms, mindful journaling stations and deep, soaking tubs in the Sanctuary Suites.

The impossibly thick, forbidding wooden doors still close with a goosebump-inducing "thunk", and it's impossible not to marvel at the way the queen-sized bed takes up almost the entirety of a single cell.

There's some serious cognitive dissonance in lying on sheets with a pleasingly high thread count while a minibar stocked with Victorian wines and craft beer is just a few steps away in what would once have been the next-door neighbour's cell.

But unlike some other prison hotels around the world, the Interlude is no place for prisoner cosplay. There's a respect for the history of the building, and its former inhabitants, who include Ronald Ryan, the last man hanged in Victoria.

"In the days of Ned Kelly, the prisoners were locked down for 23 hours a day and weren't allowed to talk in the exercise yard. They were certainly challenging conditions for anyone to live in," says the Interlude host Dylan Bedford as dusk falls. "But what's striking now is how calm it feels sitting out here as the sun goes down."

We're sitting near a crackling fire pit in the former B Division exercise yard - perhaps wisely it's now rebadged the Reflection Garden - where the hum of outside traffic is muffled by the thickness of the walls. Overlooked by the all-seeing watchtower, the once-grim scene is softened by native plantings, while cheese and red wine do their bit to loosen the mood.

As Dylan explains, colonial residents of the area suffered such stigma over living in Pentridge, Coburg's original name, that they demanded a change. "Pentridge College", as it was known by the criminal clique, was decommissioned in 1997, about the time the area around it began gentrifying.

These days Coburg is humming with the energy of its new Pentridge entertainment precinct, which includes the BrewDog urban brewery, a Palace cinema and the next-door Adina Apartment Hotel.

The group around the fire includes fellow guests Donna and Adam, Coburg residents who have witnessed first-hand the evolution of Pentridge from a no-go zone into an urban playground.

"It's been amazing to watch," says Adam. "We visit the precinct quite a bit for the brewery and the cinemas. Actually getting to stay here is pretty amazing."

Signature experiences like the dusk campfire are at the heart of Interlude. Each guest's stay comes with an itinerary packed with activities prioritising food, wine, wellness and indulgence.

My own timetable includes a leisurely float in that incredible swimming pool (it's booked as a private experience, which makes it even more magical), plus an hour-long relaxation massage in the adjacent candlelit treatment rooms with soothing essential oils.

A much-needed nap later, a wine masterclass with Interlude wine curator Liinaa Berry is an engaging journey for boffins and beginners alike. "It's a safe space to ask any questions you like," she declares before beginning a blind tasting game of "what grape variety is that?".

Berry's 500-strong list is a star at the two on-site eateries that are open to the general public as well as Interlude inmates.

Wine bar Olivine repurposes former cells into cosy, velvet-upholstered drinking nooks (surely the prisoners would have approved of this development) while restaurant North & Common has turned the former B Division canteen into a critically acclaimed modern Australian restaurant, with executive chef Mark Glenn delivering citrus-cured cobia, grilled ox tongue with cashew cream and a luscious spanner crab risoni. It's a long way from prison gruel and the horrors of institutional dining in any era.

I retire to my suite determined to see if the room comes with paranormal baggage, but the bed proves so guilt inducingly comfortable I can't report if the ghost of Ned Kelly drifted through in the night.

As rehabilitations go, the Interlude is a model prisoner. It leaves me refreshed and replenished body and soul - but if I'm being totally honest with the parole board, I'm not entirely ready to rejoin society.

The writer was a guest of the Interlude. The Interlude is halfway between the airport and Melbourne's CBD, which are around 20 minutes in each direction. Rooms at the Interlude start from $699 a night, including a bespoke stay itinerary. If you're taking public transport, the No. 19 tram from Elizabeth Street will deposit you a three-minute walk from the hotel. Explore more: pentridgecoburg.com.au