The Silent Twins – A System’s Fatal Failure

On 9 March 1993, after eleven years behind the walls of Broadmoor, June and Jennifer Gibbons were driven to a lower-security clinic. Jennifer slumped in the car and was dead that evening. The official cause was acute myocarditis, a sudden inflammation of the heart muscle. Hours later, June began speaking to staff, then to journalists, and said something stark: one of them had to die so the other could live. Natural causes on paper. An apparent pact by testimony. Those two statements do not sit comfortably together.

The Concept

This case reads less like an oddity of twin psychology and more like a sequence of institutional misjudgements. A pair of anxious, isolated teenagers with selective mutism and a private speech pattern were pushed through systems that did not understand them. Bullying crowded out school. A failed separation made things worse. A brief crime spree brought them into court, where their silence counted against them.

The result was an open-ended sentence to Broadmoor, a high-security psychiatric hospital better known for violent offenders. What should have been tailored care became an indefinite punishment, with consequences that ended in a death no one has explained to a reasonable standard.

The Questions

• How did the education and mental health systems in 1970s and 1980s Britain miss the root causes of the twins’ silence and compound their isolation?
• Was indefinite detention in Broadmoor a proportionate response to arson and theft by two 19-year-olds, or a decision shaped by their refusal to speak?
• What do the diaries and novels tell us about a relationship that swung between devotion and violence?
• What exactly killed Jennifer, and does the verdict of ‘natural causes’ hold when set against medication history, the timing of the transfer, and the alleged pact?
• How far did race shape how the twins were seen and treated?

The Unheard World of Haverfordwest

June and Jennifer were born on 11 April 1963 at a British military base in Aden to Barbadian parents. Their father worked as an RAF technician, so early childhood meant moves and new schools. The picture sharpens when the family settled in Haverfordwest, West Wales, in the early 1970s. The twins became the only Black children in their school. Accounts from family, clinicians, and later reporting describe routine bullying and overt racism. Teachers sometimes let them leave early to avoid attacks. The message they absorbed in corridors and playgrounds was simple. Keep your head down and get away fast.

By adolescence they had stopped speaking to almost everyone outside their dyad. The clinical label is selective mutism, a persistent failure to speak in certain settings despite normal ability to speak elsewhere. Today it sits under the anxiety disorders. It is not simple stubbornness. It is an avoidance pattern welded to fear. In the twins’ case, the selectivity was extreme. They spoke to each other. Sometimes to a younger sister. Barely to anyone else.

They also used a rapid, idiosyncratic speech that sounded like a private language. The term for that is cryptophasia, literally ‘secret speech’. In most twin cases, it is not a truly invented language. It is a fast, shared dialect built from the home language, shaped by speech errors, and reinforced because the twins mainly talk to each other. For June and Jennifer it likely mixed rapid English with hints of their parents’ Bajan Creole. Listeners in 1970s Pembrokeshire heard speed, unusual rhythm, and unfamiliar sounds. Outsiders called it gibberish. To the twins it worked fine.

The system tried to intervene.

Educational psychologists assessed them. A speech therapist, Ann Treharne, recorded the girls alone in a room and heard fluent exchanges. Staff then tried what many textbooks of the day recommended, separation to promote individuality.

In 1977, the twins were placed apart at St David’s Adolescent Unit. June went near catatonic, barely moving or eating. Jennifer grew more withdrawn and sometimes aggressive. The plan was dropped. The lesson should have been obvious. Whatever this bond was, it could not be pulled apart by force without serious harm.

The Bedroom as a Publishing House

They left school at 16 and retreated to their shared bedroom. The house became a stage for Americanised doll plays and home made ‘radio shows’. At Christmas 1979 they received diaries. The floodgates opened. Over the following years, they wrote vast private journals, short stories, and novels.

June’s novel The Pepsi Cola Addict followed a troubled American teenager. No publisher would take it, so the twins pooled benefit money and paid a vanity press to print it. Jennifer wrote manuscripts with titles like The Pugilist and Discomania. The themes were unflinching. Desire, rejection, violence, and the lure of transgression. Their writing did two things at once. It gave them a way to express everything their silence bottled up. It was also a bid for recognition from a world that had treated them as oddities. Each rejection letter pushed them further back inside.

There is a temptation to romanticise this period as pure creativity. Read the diaries alongside the fiction and you meet two young women swinging between ambition and despair, between affection and lethal resentment.

June wrote of being ‘enslaved’ by Jennifer. Jennifer wrote of wishing June had died at birth. They loved and feared each other. They mirrored each other’s gestures. They also hit, scratched, and sometimes strangled. The relationship was a closed circuit where tenderness and cruelty shared the same socket.

The diaries, reportedly running to over a million words, show a relationship of terrifying intensity. June wrote: ‘There is a murderous gleam in her eye… I am scared of her… She is not normal… Someone is driving her insane. It is me.’ Jennifer’s entries were equally chilling: ‘She should have died at birth. Cain killed Abel. No twin should forget that.’ This wasn’t typical sibling rivalry. This was something far more complex and dangerous.

From Fiction to Felony

By late 1981 the writing did not feel like enough. The twins were drinking, experimenting with drugs, and spending time with a group of American youths from a nearby base. Sex, bravado, and taunts bled into the diary pages. The entries describe the thrill of fire and a wish to feel something powerful enough to charge the prose. One of the boys joked about arson after a wig caught fire. The idea stuck.

For about five weeks that autumn, the twins roamed Haverfordwest at night. They smashed windows, stole small items, and set fires. A tractor shop. A technical college. Arson is not a victimless crime. Fire kills quickly and unpredictably. They were caught in November trying to ignite another building. Police seized the diaries. Courts tend to hate diaries like these. Violent fantasies on paper turn into markers of risk once they sit in an exhibit bag.

The diaries show bravado and disgust, but they also show something close to a performance. If you have no voice in public, spectacle becomes a language of its own. Fire is a blunt way to be heard.

The Sentence Without an End Date

Swansea Crown Court, 1982. The twins were 19. They barely spoke in court. The judge accepted guilty pleas to arson and related offences with almost no audible words from the defendants.

A psychiatrist from Broadmoor, Dr John Hamilton, advised that hospital detention would be suitable and that treatment might take years. The Mental Health Act framework allowed for detention ‘for treatment’ without a fixed term if doctors and the court believed it necessary.

Here is the practical effect. For crimes that usually led to two or three years inside, the twins were sent to a high-security hospital holding some of the most notorious killers in Britain. Their sentence was not measured in months. It was measured in the opinions of clinicians and the caution of administrators. June put it in one line years later: ‘We got twelve years of hell, because we didn’t speak.’

Was this lawful within the text of the Act? Yes. Was it proportionate as a matter of judgment? That is the question this case keeps pressing.

The decisive factor appears to have been their silence and the impression it created. In the courtroom and the consulting room, people who will not speak are often treated as people who will not cooperate. Risk assessment in that frame tends to climb. Treatment plans become containment plans.

Eleven Years in Broadmoor

Broadmoor is a Victorian institution with a national role. Hold and treat those deemed both mentally disordered and dangerous. The twins arrived as two of the youngest patients on site. Their presentation was unusual for the place. Their violence was largely towards each other. Their public behaviour was withdrawal, not predation.

The clinical file labels shifted. At points, staff wrote schizophrenia. Earlier legal paperwork used a category that, in that era, was called psychopathic disorder. Later commentators suggested autism spectrum traits. None of those labels explains the whole picture.

What did happen is clearer.

High doses of antipsychotic medication were used for long stretches. Concentration and motivation flagged. Jennifer developed tardive dyskinesia, the involuntary movements that can appear after long exposure to these drugs. Attempts to split the pair inside the hospital led to shutdown in one and agitation in the other. Keeping them together brought back the old cycles of imitation and assault.

A journalist, Marjorie Wallace, began visiting, read their diaries, and built trust. Through her, the public later heard the line that made the case famous… the sisters believed one had to die so the other could live freely. Call it a myth, a belief, or a fixed idea, it sat there for years like a loaded device with no known trigger.

The Final Transfer and a Fatal Fulfilment

On 9 March 1993, after eleven years, officials moved the sisters from Broadmoor to Caswell Clinic in Bridgend, a step down in security.

June later said Jennifer had been strange the previous day. Slurred words. A flatness in her face. During the journey, Jennifer put her head on June’s lap and slipped into semi-consciousness. At Caswell she was unresponsive. She died that evening in a general hospital. The post-mortem said acute myocarditis. The inquest returned a verdict of natural causes. Toxicology showed no poison or overdose.

That should end it. It does not.

The context is doing too much work for a tidy conclusion. For years they had been on heavy antipsychotics. Some of those drugs carry small but real cardiac risks. Even if nothing was in her blood that day, cumulative effects are plausible.

Leaving Broadmoor was the most significant change of their adult lives. The alleged pact adds a psychological charge that is difficult to quantify and impossible to ignore.

Wallace and the mental health charity SANE objected to the inquest. Wallace argued the jury had been denied crucial information. They hadn’t heard expert testimony about the multiple potential causes of myocarditis, including viral infections and drug-related factors. They hadn’t been given sufficient evidence about Jennifer’s care at Broadmoor in her final days, and the coroner had declined to call additional witnesses from the hospital despite the family’s request. Broadmoor conducted an internal review, the results of which were never made public. The family’s trust was broken for good.

Minutes, hours, then days after the death, June spoke. To staff. To Wallace. To cameras for a BBC documentary the following year. She said she was free. She also said Jennifer had given up her life so she could live. Soon after, June was living quietly in West Wales, no longer under psychiatric care. That is another awkward collision of facts. Silence all her life. Speech after a death. Freedom that looks like proof of a pact to those who already believe it and like a release of pressure to those who do not.

Sources

Sources include: contemporaneous court reporting from The Western Mail and other local newspapers on the twins’ 1982 trial at Swansea Crown Court; the official inquest record into Jennifer Gibbons’ death and associated post-mortem findings; archival BBC footage, notably the 1994 documentary Silent Twins: Without My Shadow, which includes June Gibbons’ first post-Broadmoor interviews; Marjorie Wallace’s book The Silent Twins, based on extensive diary access and repeated visits to Broadmoor Hospital; interviews conducted by Wallace for SANE and other media outlets; surviving excerpts from the twins’ unpublished manuscripts and personal diaries, as reproduced in authorised publications and broadcast features; secondary academic literature on selective mutism, cryptophasia, and the psychiatric treatment of young offenders in the UK in the 1980s; historical sentencing data for arson and related offences from the Home Office and contemporary legal commentary; independent commentary on the role of race in the twins’ schooling and clinical assessments; and publicly available information on Broadmoor Hospital’s regime, staffing, and patient management practices during the period 1982–1993.