It was just after 6pm on a summer evening when two gunshots shattered the silence of a suburban street in Plymouth. Jake Davison had murdered his mother, Maxine, with a pump- action shotgun. Over the next 12 minutes, roaming the streets near the family home, the apprentice crane operator killed four other people and left two more with life-changing injuries.

In a chilling detail, a witness recalled seeing Davison calmly walking as if he was ‘on patrol, like a soldier with a gun’. First, he shot and killed Lee Martyn, 43, and his three-year-old daughter, Sophie. Then he shot through the door of a house, injuring a mother, 53, and her 33-year-old son.

Turning a corner, the 22-year-old killed Stephen Washington, 59, then Kate Shepherd, 66. He continued walking towards a nearby hair salon, where he stopped outside and fatally shot himself.

I read about the carnage with sadness and horror. The killings seemed inexplicable, but it transpired that numerous warning signs had been missed.

The shotgun Davison used to kill his mother, his neighbours and himself in August 2021, was legally held, despite him having a history of violence and mental health issues. His online activity showed a disturbing identification with ‘Incels’ – a subculture of ‘involuntary celibate’ men who had failed to attract sexual partners and developed a hatred of women as a result.

WARNING SIGNS: Mass killer Jake Davison, 22, who had mental health problems and a known history of violence

He had posted messages referencing ‘blackpilling’ – having a nihilistic world view – and had been taking anabolic steroids, which are banned in the UK.

Davison’s mother often argued with him about his sexist attitudes and was so worried about his isolation and ‘unhealthy’ obsession with guns in his mid-teens that he was referred to Prevent, the Government’s counter-extremism programme.

In 2020, Davison became violent, attacking and punching an innocent 16-year-old boy until he was unconscious. When a girl tried to intervene, he slapped her in the face. The incident was caught on CCTV, so there was plenty of evidence with which to charge him with actual bodily harm, which carries a prison term of up to five years.

But with the criminal justice system overloaded, police were under pressure to use out-of-court methods of dealing with ‘low-level’ offences. Instead of being prosecuted, Davison was ordered to attend a ‘Pathfinder’ course to be rehabilitated – a police-endorsed, 16-week course that aims to explore the reasons for the offence and then create individually targeted strategies to prevent the person offending again.

The Pathfinder course has a Twitter feed, which gives some insight into its approach.

A photo of a whiteboard says, ‘If you rearrange the letters in DEPRESSION you’ll get I PRESSED ON.’ There is also a GIF of a cute puppy waving its paw in the air, with the caption “High 5!”’

To be fair, it was during one of its fluffy sessions that a member of staff became concerned about Davison and told police he possessed a gun and a referral was made to the firearms department, with Davison’s shotgun being seized and his licence revoked.

By March 2021, though, he had ‘successfully’ completed the Pathfinder scheme and in July the police handed back the gun. A month later, he used it to murder five people.

As a filmmaker and writer, I’m in a unique position to look at the chaos in our criminal justice system. In 2016, I was sentenced to five years for tax fraud, and spent two-and-a-half years inside, beginning at HMP Wandsworth and ending at Spring Hill open prison.

My book about that journey has since given birth to a popular podcast where I interview more than 20 ex-prisoners. What has struck me most, as I have returned to my old life, is how many of them have landed back inside.

Reoffending is the hidden scandal of our times. The UK has among the worst recidivism rates in Europe, with 45 per cent of adult ex-prisoners reconvicted within one year of release. For people serving short sentences, this rises to 61 per cent – and, given that large numbers of crimes are never even prosecuted, the real number of reoffences will be much higher.

SHOT DEAD: Jake Davison’s mother Maxine, 51 – the first to be killed in her son’s shotgun rampage – Kate Shepherd, 66, and Stephen Washington, 59

Reoffending costs the taxpayer about £18 billion a year, which is roughly a quarter of the education budget and more than half what we spend on defence.

Around 80 per cent of those receiving cautions or convictions have offended before. Turning this statistic on its head shows just how deep the problem runs. If we solved reoffending, we’d prevent 80 per cent of all crimes.

Some 90 per cent of offenders are automatically released after serving only half their sentences; the rest is spent out in the community, supposedly being rehabilitated by the probation service. But the system is in chaos after a disastrous attempt at privatisation that wasted £500 million of public money and was condemned as an ‘unmitigated disaster’. The probation service has since been re-nationalised but is under-staffed and under-funded.

So, perhaps it’s not surprising that, where possible, offenders such as Davison have been subject to out-of-court-disposals: but that means they never make it as far as prison or probation at all.

My investigation into the Plymouth shootings took me to the inquest into the deaths of Davison’s victims earlier this year. Their families had been waiting 16 months for answers. Some were holding hands, ready for the gruelling day ahead.

A lawyer began by reading a statement on behalf of Rebecca Martyn, wife of Lee Martyn and mother of Sophie.

‘Lee Martyn was a promising young footballer, who had trials for Watford in his teens.

‘We married in 2009 and had two children, Caden and Sophie. He took several months off work during the pandemic and loved spending the extra time with his kids, having water fights in the garden.

‘Sophie was Daddy’s princess… On August 12, Lee made everyone macaroni cheese, and then took Sophie out for a walk. I later discovered she must have taken one of her teddies out in the pram. She would always push the buggy a short while, before giving up and one of us had to carry it home.

‘I sent Lee a WhatsApp at 6.13pm to see what he was doing. The message received two grey ticks, to indicate it was delivered but never read. I went to look for them and saw there was a police cordon in the road. An officer took my details, which he wrote on a glove. I got back home, the police later arrived to say they had both been fatally shot. Sophie was just three years old.’

The whole room sat in stunned silence. Rebecca stared straight ahead, tears flowing down her face.

Sheila Washington approached the microphone on crutches. Her husband, Stephen, was her full-time carer. He went out for a quick walk with their two dogs, calling out: ‘See you in a bit, won’t be long.’

GUNNED DOWN: Lee Martyn, 43, and his daughter Sophie, three

Sheila later heard some bangs outside, followed by one of the dogs scratching at the door to get back in. ‘I’m still coming to terms with Stephen’s death. I never imagined losing him in such horrendous circumstances,’ she said.

Kate Shepherd’s son delivered a moving speech about his mother, remembering how she was a much-admired artist.

‘She was colourful in painting and textile designs, colourful in her attitudes – and colourful in her language.’ His voice cracked as he explained that she became a grandmother for the first time a few days before the incident.

The fateful decision to put Davison on the Pathfinder course got only a brief mention at the inquests, and there was no attempt to verify whether it worked as sold.

Devon and Cornwall police had long been proud supporters of the scheme; the force’s website calls Pathfinder ‘an evidence-based intervention that reduces harm and reoffending and can hold offenders to account for their actions… while addressing needs that are directly linked to their offending’.

What I’ve discovered tells quite a different story.

Pathfinder is run by a charity called the Centre For Justice Innovation, which claims to ‘put evidence at the heart of justice reform’. Its website has a lot of warm words about the scheme, including some glowing, anonymous testimonials and the completely unsubstantiated, as far as I am aware, claim that ‘84 per cent of offenders said that Pathfinder had “helped a great deal” in reducing their risk of reoffending’.

Offenders attend these courses as an alternative to prison, so it’s hardly surprising they gave Pathfinder the thumbs-up.

Jake Davison said he found the Pathfinder scheme to be a ‘positive experience’, teaching him ‘the importance of self-discipline’, but we all know that wasn’t exactly true.

Looking at the charity’s website in the aftermath of the shooting, I can see no evidence to support the police’s claim that the programme lowers reoffending, though it does mention a study carried out in 2018 as part of an evaluation with Cambridge University, which it promised to publish in full in 2021. The charity did not publish the study in 2021. In January 2022, I emailed, asking for a copy, but they did not respond to my numerous emails and phone calls.

I have discovered that the authorities have form for burying bad news about reoffending programmes. For instance, the Sex Offender Treatment Programme, introduced in prisons in 1991, promised to cut reoffending among paedophiles and rapists and cost more than £100 million before an internal Ministry of Justice (MoJ) study concluded that the programme did more harm than good – it actually made future attacks more likely.

The 2012 report that reached this conclusion was suppressed to avoid embarrassment. It was only when it was leaked five years later that the course was finally shut down.

I emailed the MoJ, which has overall responsibility for the probation service and courts, asking what evidence was provided to support Pathfinder when the course was officially accredited.

The response was shocking: the Pathfinder course had never been accredited by the government panel that reviews reoffending courses.

How then, could Devon and Cornwall police be claiming Pathfinder definitely reduced reoffending?

I asked them to substantiate the claim and requested a copy of the mysterious study from Cambridge.

The police refused, claiming that the results were still being submitted for peer review – the process by which studies are independently checked.

So, I ploughed on, until the police finally made the startling admission that only part of the scheme was tested. Pathfinder is basically two courses: a lighter version for people accused of minor offences, to defer their cautions; and a tougher version for perpetrators of more serious offences, such as actual bodily harm (ABH) to defer their criminal charges.

The Cambridge researchers only looked at the deferred caution element and not the deferred charge version – the scheme relevant to the most dangerous offenders, and the one on which Davison was sent.

This means that the biggest mass killer of the past decade went on an unaccredited community rehabilitation course that the police have falsely, it seems, claimed is proven to reduce reoffending.

The police’s apparent misplaced faith in Pathfinder was fundamental to Davison being allowed, legally, to possess firearms again.

An internal police document revealed why the firearms inquiry officer made the decision to hand back the gun: ‘I am happy that the situation was dealt with by referring Jake to Pathfinder and that it has had a positive effect on Jake… I assess Jake as low risk.’

Such is the power of these courses that officers didn’t even bother to look at the CCTV footage of Davison’s violent assault. Instead, they relied on their own claims about Pathfinder’s efficacy. Attending the course was enough to reinstate the firearms licence, a decision the coroner later ruled was ‘fundamentally flawed’.

Wrongly relying on Pathfinder was just one of many errors that led to the Plymouth shootings.

Davison’s doctors didn’t tell the police about his mental health issues before the shotgun licence was issued; the police department responsible for issuing firearm licences was chronically understaffed; the officer who initially assessed Davison had no formal training whatsoever and seems to have ignored his history of violence at school. The police later admitted they had a culture that was ‘too tolerant of risk’ and that Davison should never have been given his gun back.

But if the police hadn’t relied on Pathfinder, Davison would have been convicted of ABH, his shotgun would almost certainly not have been returned – and his victims would still be alive.

WEAPON: The pump-action shotgun Davison used on his killing spree

After the inquests, in March 2023, the Centre for Justice Innovation was still promoting the Pathfinder scheme.

To my surprise, it also claimed that the Cambridge study (which it still wouldn’t publish) showed the course triggered a seemingly incredible reduction in reoffending to just 3 per cent – but its website excluded the key fact that this was only measured while the offenders were on the course.

By this method, Davison counts as a Pathfinder success story, as he waited until after he’d completed the course to murder five people. It’s akin to promoting a new drug because there were no side effects during a clinical trial, while hiding the fact that half the participants died shortly afterwards.

Even courses that are fully accredited by the MoJ are prone to making questionable claims about their effectiveness.

RISE Mutual is one of the many companies that have thrived out of a privatised probation service.

It has been paid significant sums of public money to run several reoffending courses in the community, including Building Better Relationships, Thinking Skills, and Resolve. The company’s website says these courses ‘have proven that people can change’ and boasts of an ‘evidence-led approach’.

Davison also completed a Thinking Skills programme, which added weight to the police’s misplaced belief he had been rehabilitated.

A thorough search of RISE Mutual’s website, and beyond, reveals no proof to back their claims. When I asked the head of the company, Clare King, for evidence, she replied, admitting: ‘I’m not able to provide this information… We have a licence to deliver them [the courses] from the Ministry of Justice but did not design them. You would need to contact the… MoJ to ask for the evidence base.’

And when I did, the MoJ doesn’t have any proof either.

It has simply published a ‘reoffending impact evaluation’ for the Thinking Skills programme, which was conducted as part of an HM Prison and Probation Service employee’s PhD.

While Dr Rosie Travers must be thrilled her coursework has been used to justify thousands of pounds being spent on the rehabilitation programme, her thesis contains no hard evidence that it works.

In response to my investigation, RISE Mutual dropped the courses in question, but many others are still running and, depressingly, a former probation officer tells me she still believes the courses are worthwhile, even if they don’t work in the long run. ‘If the offender has to sit in a classroom for an hour, it means they’re not on the streets causing trouble. Someone can at least keep an eye on them, and they’re not spending that time selling drugs or mugging people,’ she says.

That’s a fair point, but is it really the best we can come up with – a programme of reform so ineffective that someone like Jake Davison, a ‘successful’ graduate of Pathfinder, went on to kill?

© Chris Atkins, 2023

Adapted from Time After Time: Repeat Offenders – The Inside Stories by Chris Atkins (Atlantic Books, £20) to be published on September 7. To order a copy for £18 (offer valid to 17/09/2023; UK p&p free on orders over £25) go to mailshop.co.uk/books or call 020 3176 2937.