Is there a cure for Britain's most dangerous criminals?

Jeremy Laurance meets Dr Gwen Adshead, forensic psychotherapist at Broadmoor Hospital

Derek and Jean Robinson were a kindly couple who lived in a neat house in Heslington, York. He was a doctor and she worked for Christian Aid. It was the early 1970s; I was a student at the university, and my father, who knew them, had urged me to make contact. I spent a pleasant hour in their kitchen, chatting over coffee, and then took my leave, promising, as one does, to see them again soon. I never did. The next I heard, more than 30 years later, was that they had been murdered by a man with a psychopathic personality disorder who told police he wanted to become Britain's most prolific serial killer.

Daniel Gonzalez was sent to Broadmoor for the murders in 2006. He attacked six people in 48 hours, killing four of them. He is thought to have broken into the Robinson's house early in the morning – they had moved to Highgate, north London by this time – and stabbed both of them to death in the hallway. It was a pointless, motiveless, random killing. Could anyone make sense of it? Could Gonzalez?

In Gwen Adshead's view, killers like Gonzalez must be helped to try. As a consultant forensic psychotherapist – a rare breed in medicine – she spends her working life in the company of men at Broadmoor whom others would dismiss with a single word – evil. Her aim is to make them safer – safe enough, ultimately, to be released from Britain's highest security institution for mentally disordered offenders – and to achieve that they must understand the full import of the crime they have committed.

"My job is to help a man become more articulate about what he has done, about his illness and about why that might be important for his future. Even if a cure is not possible, recovery of some identity is possible. My work involves talking to them and getting them to become more self-reflective. Violence is more likely to occur when people are not thinking straight."

Admission to Broadmoor is granted only to members of an exclusive club: the violent insane. The Yorkshire Ripper, Peter Sutcliffe, is here, convicted in 1981 of murdering 13 prostitutes; Kenneth Erskine, the Stockwell strangler who murdered seven elderly people in 1986; and London nail bomber David Copeland who targeted blacks, Bangladeshis and gays, killing three people and injuring 129, of whom four lost limbs. But what does "insane" mean? How different are they from the rest of us?

Adshead, who is 50, is wearing a dark jersey top, a long olive skirt with a string of pearls at her neck and around one wrist. She could pass for an art college lecturer or a rural GP but for one detail – the leather pouch on a belt around her waist carrying a jangling bunch of keys.

Her tiny office is strewn with papers – she has to move some to make space for my mug of tea – and the filing cabinet next door contains folders marked "Evil and moral reasoning", "Toxic attachments", "Hope and hate". She was brought up in New Zealand – her parents were both academics – and she is writing a book on the nature of evil to be published by Jessica Kingsley next year.

"I have always been interested in how other people's minds work. I was an internalist – on the spectrum I was towards the introspective end. If you are interested in how the mind goes awry and how organisations should respond, then you are going to gravitate to a place like Broadmoor," she says.

It was her appearance on Desert Island Discs earlier in the summer that brought Adshead – and Broadmoor – some unexpectedly positive and welcome attention.

She described the patients – "our people" is a favourite phrase – as not mad or bad but sad. She quoted Shakespeare's phrase from King Lear – "ruined pieces of nature" – and explained that her job had become harder when she had her two sons, who are now school age.

"Their arrival changed my view. I imagined these men as the beautiful babies they must have been – or as round-headed eight-year-olds. All that promise... how sad it is," she says.

The impression was of a humane, empathetic doctor with liberal instincts trying to do her best for people who are more often regarded as depraved monsters, fit only to be locked away for life.

Some of them, unavoidably, will be. But for the rest, if they can be made safer in themselves, then those around them will be safer – and they may be able to move on.

"Our people have been really dangerous and there is a risk they will be again and the Government is entitled to take steps to protect the safety of the public. Slaughter-ing your family is, we can agree, an undesirable thing.

In ordinary psychiatry there is a lot of debate about paternalism. Psychiatrists have the power to detain people against their will and there is debate about when that power should be used. The issues are much starker here – there is no grey area over whether they have done something horrible or mad. Ordinary psychiatry is much woollier than that."

She likens what she does to providing palliative care for cancer – not trying to cure, but trying to ease the symptoms so that the patient is more comfortable, more serene and more secure.

"They may be mentally ill or they may not be, but have very disorganised ways of thinking. They may not have lost touch with reality but they may have talked themselves into an alternative reality. Like the Royal Marsden [the hospital in London which provides specialist cancer care], we deliver highly specialised long-term care to very disabled people at Broadmoor."

She never got a chance to help Gonzalez. Once he arrived at Broadmoor he set about attacking his seventh victim – himself. He attempted suicide by opening the veins in his wrists with his teeth – one psychiatrist said he had never seen anyone bite himself with such ferocity. He was placed on heavy doses of anti-psychotic and tranquillising drugs and he put on four stone in weight in a year – a side effect of the drugs. But he never lost his desire for self-destruction. In 2007, three years after his admission, he finally succeeded in ending his life, slashing his wrists with the plastic edge of a CD case.

Making patients safe sounds like a limited ambition for a doctor, trained to cure disease and make the ill well. Moreover, once admitted, there is no going back to normal life. Patients at Broadmoor have a one-way ticket – most face a lifetime in institutions. "Release" means to a psychiatric unit elsewhere with a slightly lower level of security.

The institution, a sprawling 250-acre plot, is situated in Crowthorne, Berkshire, a prosperous Home Counties village. The 12-metre-high red brick perimeter wall and steel pylons carrying search lights are all most local residents see of it. They hear it, however – every Monday morning the siren is tested for two minutes. It was installed in 1952 after child killer John Straffen escaped – within two hours he had murdered another child. If the siren sounds for real again, local schools are under instructions to lock their doors and keep their children inside. But the last escape happened so long ago not even the staff can remember when it occurred.

The average Broadmoor patient – they number around 250 in all – stays six years before moving on. Dr Adshead has been in her post for 10 years. She would be quite content, she says, to end her career there, though she winces when I mention the health regulator, the Care Quality Commission's negative verdict on Broadmoor last year. It painted a grim picture of an institution blighted by weak management, poor staffing and training, inadequate facilities and overcrowding.

Concerns about Broadmoor's failure to properly care for its patients have been raised repeatedly over the past 20 years. In 2003, the hospital was described as "totally unfit for purpose" and lacking "basic standards of dignity and privacy" by the Commission for Health Improvement, a former NHS regulator. "That remains the case today," the CQC said in its 2009 report.

It is, of course, harder to deliver high-quality medical care under conditions of tight security. Is Broadmoor a prison or a hospital? It is a sensitive issue – a press officer sternly corrects me when I carelessly refer to its residents as "inmates". They are patients, I was reminded. Until a decade ago, most of the staff were members of the Prison Officers Association, but today that has changed and most are now members of nursing unions.

Nevertheless, a visitor to the hospital – a mix of Victorian and modern buildings arranged around a bleak campus of clipped grass bisected with high walls and steel fences topped with razor wire – is left with one overwhelming impression: the jangling of keys. Every gate and every door must be unlocked and relocked. Some are released remotely by unseen guards – to foil any patient who, having seized a bunch of keys, should try to escape.

In the Paddock Centre, the unit for men with DSPD (Dangerous Severe Personality Disorder), I am accosted by a patient returning from the gym. On learning that I am a journalist, he launches into a passionate denun-ciation – articulate, intelligent and well-informed – of the law which allows people deemed "mentally disordered" to be detained without limit of time while ordinary criminals are released once their sentences have been served. "It's a disgrace," he spits, and then breaks into a laugh. Insane? He did not seem so.

Like all hospitals, Broadmoor has an "admission" ward where new patients are assessed. Its double meaning has always struck Adshead as apt. When she goes into a new interview with a patient she has to be wary, but she has only been threatened once in 10 years – by a serial rapist. "He quickly became intimidating, threatening me with lawyers, saying I had no right to ask him questions. In retrospect I should have thought he might find a strange female disturbing."

One of Adshead's themes is the rarity and randomness of violence – not only in those who are victims of it but in those who commit it. "Human beings are not predictable. The capacity for doing horrible things is there in all of us. But happily very few will actually do it. The road between the two is very long and there are lots of escape routes off it."

She spells out the pre-conditions that increase the risk: childhood adversity, substance abuse, serious psychotic illness. Even then, violence only occurs when a fourth factor clicks into place – "and that could be any damn thing".

A few months before Daniel Gonzalez stood trial for murder in 2006, I had coffee in the kitchen of another neat, suburban house, not unlike the Robinson's, with his mother, Lesley Savage, a civil servant. There was a bowl of oranges on the table, plumped up cushions in the lounge and a carefully tended vegetable patch in the garden. The only sign of the violence her son had unleashed was a small dent in the stainless steel sink where he had stabbed through the plastic washing-up bowl with a kitchen knife before running out of the house at the start of his two-day killing spree.

Mrs Savage's plea, like Adshead's, was for understanding – but before the violence, not after. Her complaint was that the authorities had ignored her increasingly desperate cries for help during a decade-long struggle to get treatment for her son. She had written dozens of letters and made scores of phone calls to social services departments, mental health services and doctors pleading with them to do something. She showed me one letter, dated 22 June, 1998. It said: "Does Daniel have to murder or be murdered before he gets help?"

Dr Adshead's commitment to making Broadmoor's patients safer, through putting them in touch with themselves, is admirable. But one cannot help wondering why it should have been so difficult to achieve the same end before tragedy struck. Then Derek and Jean Robinson might still be enjoying their retirement, Daniel Gonzalez might be forging a future for himself and Lesley Savage able to take pride in her darkly handsome son.