Oxford Castle once provided brutal bed and board for those staying at Her Majesty's pleasure, but now it's a luxury hotel and caters to people seeking their own. ONELIFE heads inside the joint to do some time.

The door of the jail cell shuts heavily behind me and I peer into the semi-darkness of the room. Prisoners who have done time in here before me would have heard that door slam day after day and known they were hopelessly trapped. Some of them would have spent years in this cell, counting the hours, enduring hardship with an anguish and impotent rage that seeped into these very walls. I pause at this melancholy thought—but I can only resist for a moment before I have to run and throw myself gleefully onto the enormous soft bed. Well, this is a hotel, isn't it?

Welcome to Malmaison Oxford, a UK hotel where sane adults really do pay to spend the night in a prison cell. Or three cells, to be precise. The architects who converted the former HM Prison Oxford into this modern hotel have kindly merged three cells to form each guest room—looking up, you can see where steel joists in the ceiling mark the confines of the tiny original cells. Until the prison shut in 1996, three inmates were crammed into each of these spaces—the phrase "not enough room to swing a slop bucket" comes to mind. I, on the other hand, have room to swing any number of slop buckets should the mood take me, although given the very adequate bathroom facilities, this would be unnecessary.

And there's obviously not just the space to be happy about. Each room comes complete with comforts I suspect would not have been provided for former inmates, from a fancy wall-mounted plasma-screen television to grapefruit-and-shea-butter hand soap. Yes, I think I can bear my night locked up in here quite easily, thank you very much.

I'm intrigued to find that in my cell door there is a small, one-way spyhole. It was called a "Judas hole" in its former life because it enabled the "screws" (guards) to look in and betray any prisoners engaged in mischief. These days, the Judas holes have been inverted, thankfully, giving cell-room guests like me a view outside to the long and graceful A-wing block. This vast Victorian glass atrium houses three levels of cell rooms, with whitewashed brick walls and narrow iron staircases. It's changed very little since the old days. Notwithstanding the removal of the wire-mesh suicide nets, it's a sight not wildly dissimilar to the view prisoners themselves would have been greeted with each morning when time came for "slopping out"—although they may have been puzzled by the new striped carpet and complimentary newspapers.

A leisurely stroll reveals that the hospital wing, governor's house and even the old punishment rooms have also undergone the Malmaison treatment. The result is a total of 94 very pleasant guest rooms, as well as every amenity said guests might require, including a stylish restaurant, wine bar, lounge and gym. It's all part of an $80 million conversion of the entire Oxford Castle site. Besides this swank new Malmaison hotel, there is also now a community recreation complex crowded with restaurants and cafés—these days, guests are discouraged from escaping not with bars and chains but with the compelling aroma of freshly baked Krispy Kreme doughnuts.

On the topic of "guests," Oxford Castle has had its share of notables. One of the Great Train Robbers, Tommy Wisbey, spent some of his very long sentence here, as did perhaps the prison's most notorious inmate of all—the "Black Panther." During the 1970s this character, aka Donald Neilson, was Britain's most wanted man, thanks to a series of murderous armed robberies and a fatal kidnapping. He was caught in December 1975 (when a search of his house uncovered not just a number of guns but also an unwisely displayed figurine of a black panther) and tried at Oxford Crown Court. He was considered so dangerous that a reinforced cell was specially built in D-wing to house him.