HLM Architects' PFI prison may be a regression to Victorian design values, but its pastel shades and female warders make the Salford complex humane as well as stark.
The first thing that strikes you about the new all-male, high-security PFI prison in Salford is the high proportion of women warders. This, explains one of them, has a soothing effect on prisoners. "Prisoners themselves look on it as bad form to give abuse to female warders, although they might think differently about males," she says.

The second thing that strikes you about Forest Bank Prison is the good-humoured rapport between prisoners and their guards.

One young prisoner rushes past, teasing our group of visitors and warders: "Another prison visit? But this isn't a prison, it's a holiday camp." Tim Colbourne, policy officer of the Howard League for Penal Reform, confirms that private prisons do not conform to the grim Porridge image of the traditional jail. "Prisoners have a lot of good things to say about private prisons," he says. "They are treated with courtesy and respect. That's because there's a very different culture and a better mix of staff." There are occasional lapses in what Colbourne calls "a good record of decent standards of care" in private prisons. Last July, just one week after Forest Bank was officially opened by Princess Anne, a disturbance erupted, with 40 inmates barricading themselves in for eight hours, ripping off cell doors and lighting fires. Teething problems, including defects in a new phone system, have been blamed.

Nine months later, and prisoners' jokes aside, Forest Bank bears scant resemblance to a holiday camp. Heavily barred steel doors and windows and high razor wire fences are in evidence everywhere. It is, in the words of director (private prisons don't have governors) Mike Goodwin, "functional and no-frills".

In fact, Forest Bank, which is one of the first PFI prisons, is a regression to the classic Victorian prison format, pioneered by philosopher Jeremy Bentham at Pentonville in 1840. All 800 cells are contained within elongated four-storey blocks, which are one or two storeys higher than most post-war prisons, and these are arranged as six wings that radiate like spokes from a central circulation core.

The whole complex was designed, constructed and financed by the French-owned private company UKDS, which now manages the prison under a 25-year, £204.5m PFI deal with the Prison Service. The construction cost was £46m. The PFI provider, with HLM Architects as lead designer, was given carte blanche in design, as long as it complied with Prison Service's stringent performance requirements.

A prison presents a design challenge quite unlike any other building type. For a start, a prison is not so much a building as an entire town in miniature, as Goodwin explains: "Just like a town, a prison must include a town hall, food outlets, leisure centre, school, chapel, hospital, industry, housing and even a prison within a prison." The other overriding concern is security and safety, not just to restrain prisoners from breaking out or attacking warders but also to prevent them from harming themselves and each other. Forest Bank has the additional problem of being a "local prison" that brings together four classes of inmates – convicted adults, adults on remand, convicted young offenders and young offenders on remand – who are required to be kept apart at all times. At the same time, an enlightened prison regime would try to reduce the demands on safety and security by designing out tension and antagonism as much as possible in the first place.

But in the pressure-cooker world of a prison, doing this is not simple. "In the 1970s, prisons were designed with cells opening on to narrow hotel-type corridors, where people couldn't pass each other easily," says Goodman. "In reality, they designed in antagonism, and they required far more supervision at great cost." In HLM's layout for Forest Bank, the radial configuration of the cell blocks is adjoined by a straight, 6 m wide, internal "street" that is flanked on either side by all the other prisoner accommodation, an idea borrowed from hospital design. Both these configurations fit together into a very compact complex, which takes up just 60% of the site designated in the Prison Service's original feasibility study.

The compact layout was a good selling point to the local planning authority, as the excess land could be handed over as landscaped public parkland. For its part, the long straight internal street, which is free from any recesses where prisoners could lurk and is overseen by just two CCTV cameras at either end, makes for trouble-free surveillance with minimal staffing.

But how does the high-density layout square with the desire to reduce tension among inmates? And how does the single undivided internal street make circulation easy for the four segregated groups? The exercise yards occupying the segments between the cell blocks are far from promising. Mean, dank, triangular patches of tarmac, they are tightly bounded by four-storey concrete-block walls and razor-wire.

However, Goodwin claims that the simple layout is deceptive. "You can move the different populations around to different activities such as exercise yards, sports facilities, workshops and training, with no extra level of supervision. In fact, there are as many as 100 movements of prisoners a day, many coming in and out of the prison to and from courts. It's all about timing. But you couldn't do that with a more complex, dispersed layout. This layout builds out confrontation; it provides maximum supervision for minimum supervisory staff." The relatively narrow strip of external space between the accommodation blocks and the perimeter wall is nearly entirely taken up by playing fields. Clive Badger, HLM's project director, comments: "In previous prisons, the buildings were pavilions lost in space. Here we have made the spaces between buildings usable." The layout is also more flexible than it first seems. The six four-storey cell blocks are each split into two self-contained "maisonettes" containing 62 cells, and the triangular exercise yards between them are likewise split horizontally by a central fence. This adds up to a total of 12 self-contained maisonettes and the same number of exercise yards, which is convenient for accommodating shifting proportions of segregated prisoners. Added to that, prisoners can be moved from each maisonette directly to the adjacent exercise yard without crossing the paths of other groups. Splitting the blocks into maisonettes also reduces the oppressiveness of large numbers of inmates sharing a large space and the risk of suicide jumps from the top access deck.

Given the high-density medium-rise layout, one of Badger's main concerns has been "to bring daylight into internal spaces to remove the feeling of claustrophobia". This problem was most acute in the central communal areas of the four-storey cell blocks. The upper maisonette gains ample daylight directly from a continuous rooflight, which has been raised high enough to deter escape attempts. But the lower one has no such option. Here, fully glazed gable-end walls, the inner one made of translucent glass blocks, plus a ceiling of shiny metal-faced acoustic panels and a floor of equally shiny polished linoleum, combine to bounce daylight deep into the heart of the block.

HLM Architects' other ploy to reduce tension among inmates has been to decorate internal walls and doors in a range of pastel colours that have, the practice claims, calming, anti-depressive effects. Different colours have been selected for different spaces according to psychological principles, with blue and violet – "comforting and devout, dignified" – used for the chapel and orange – "lightness, stimulating, anti-depressive" – in the cell blocks. Whether psychologically effective or not, the colour scheme is at least pleasant and also serves a more practical role as colour-coding of different areas for the many illiterate prisoners.

The individual cells themselves have also been redesigned from first principles, although within the Prison Service's space and performance standards. The service insists on "safe cells" that offer no opportunity for inmates to harm themselves. This means the elimination of sharp edges and hooks, grooves or bars from which cords could be attached.

At Forest Bank, identical pairs of cells were precast in concrete to save time and money. Internally, fittings such as bed, closet, WC and hand basin are built in. Both the WC and hand basin are purpose-designed in softly curving epoxy resin. A fixed window with toughened double-glazing and external steel bars at the requisite spacing comes with a shuttered ventilation panel below.

"It's been quite gratifying to find that our safe cell design has been adopted as standard by the Prison Service and reissued back to us," adds Badger.

Fire and smoke control is a particular problem in prisons, with hundreds of prisoners locked up individually. At Forest Bank, voids have been left between cells and smoke reservoirs created within the roof spaces.

The external walls of all the blocks have been constructed in a specially manufactured buff masonry blockwork. As external modelling was banned in the name of safety and security, the architect has enlivened the walls by counterpointing smooth and rough finishes to the blockwork.

To pacify local residents, who vociferously opposed the original proposal to build a large new prison in the green belt next to the River Irwell, UKDS has surrounded the complex and its car parking with a recreated natural landscape of screening embankments, woodlands, meadows and a new lake. In addition, relatively subdued masonry and roof finishes were chosen for the buildings. "The most common comment we get now is: 'We wouldn't have noticed it was there'," says Goodwin.

The Howard League's Colbourne argues that where prisons go wrong is not in design but in the overcrowding imposed by the courts. "New prisons rapidly fill up and then overfill," he says. "When two or three people share a cell with an open toilet, you get big problems of hygiene, health and safety. The logistics get very difficult, with prisoners locked in cells for 23 hours a day." With no sign yet of overcrowding, Forest Bank Prison seems to work efficiently with a positive attitude among staff. Though no holiday camp, the buildings are relatively safe, have a certain stark dignity and provide a humane environment for inmates. Within a high-security complex fenced in by steel bars and razor wire, that is no mean achievement.

How to develop an 800-cell prison in three years

June 1997
The Prison Service invites bids to design, construct, manage and finance an 800-cell, Category B high-security prison in Salford. Outline planning permission for the site of a former power station has already been granted by the DETR after a public inquiry. UKDS appoints HLM Architects, which has experience of designing hospitals but not prisons. UKDS chief executive Herb Nahapiet (formerly director of Mowlem) says: “We gave three architects 48 hours to make presentations, and we selected HLM straightaway because it had the imagination to cope with a process of continual change and came with no baggage.” September 1997
PFI bids submitted. November 1997
Prison Service names UKDS preferred bidder on a bid of £204.5m net present value over 25 years (November 2000 prices), which the Prison Service calculated was 13% cheaper than the public sector comparator. March 1998
Salford City Council awards detailed planning permission for a scheme that uses only 60% of the site designated in the outline approval. UKDS promises that the area around the prison complex would be decontaminated and landscaped as natural parkland and that “almost all” of the 300 prison jobs would be recruited locally. July 1998
Design-and-build contractor Tilbury Douglas starts construction. The original power station foundations are tensed, and the 800 cells are paired and precast in concrete off-site. November 1999
Construction is completed. January 2000
Forest Bank opens its doors to prisoners. “This thing has zipped along much faster than a hospital PFI,” comments Nahapiet. “There have been no delays.” March 2001
The same team has now submitted four bids for PFI prisons and has been awarded an immigrant detention centre next to Heathrow Airport.