Like most of the country, I find myself spellbound and appalled in equal measure by the extent of the very topical Post Office Horizon scandal.

As a career investigator with 40 + years of criminal and industry experience, what personally and professionally intrigues me most is the scale of apparent investigative incompetence. It appears there was blind faith in the Horizon technology data, which led to a raft of miscarriages of justice.

Rule 101 of investigations is never to rely on a single source of evidence, no matter how compelling. This provides the basis for confident and robust decision-making and assures the crucial element of corroboration.

However, there's something else to consider. As a young investigator, I recall an experienced detective counselling me that whilst forensic science and technical data, such as DNA/CCTV, for example, was compelling for the jury, I should never underestimate the importance of what he called 'gut instinct`. It's difficult to articulate what this is precisely; however, we will all have experienced when something doesn't feel quite right or seems a bit off.

Where was the investigative gut instinct?

It is this aspect which troubles and disturbs me most in this saga. I'm trying to place myself in the position of the Post Office investigation team and find it impossible to imagine that at some point, `gut instinct` didn't kick in.

Driving away from having interviewed these model citizens, pillars of the community, and having accused them of horrendous criminality in the face of denial, surely some in the team must have questioned the integrity of the Horizon technology data. It was the classic single point of failure.

The apparent financial discrepancies must have screamed at odds with the profiles and backgrounds of those decent people they were accusing, not to mention the very obvious question…why do we have such a sudden spike in postmasters and postmistresses turned criminals?

The Pervasive Impact of Investigation Bias

When that gnawing question of doubt creeps into an investigator's mind, it takes courage to raise your hand in the room and voice your concerns. I'd be amazed if hands weren't raised in this case, but were they listened to? From the outside looking in, those driving the investigation had already decided its destination and would strive to make the evidence fit the perverse outcome at all costs—investigation bias at its most rampant and destructive.

There is then the danger of reaching the perceived point of no return. Occasionally, and I have observed this several times, it may seem at the outset that the outcome of the investigation is clear and obvious. We have apparently solid data pointing in a single direction…what else could it possibly be? Time and resources later, when that initial confidence is challenged or dented by countering or conflicting evidence, it can be hard to accept and tempting to ignore.

It takes courage to accept and change investigative direction. In this case, I wonder if those at the top lacked the moral courage to admit they got it wrong and ploughed on regardless of the human misery and injustices they were causing. They had passed the point of no return! Continuing momentum when nagging doubt is often described as 'dysfunctional momentum'; it doesn't feel quite right, but we'll continue because we're all invested, and so are all of our reputations.


Hopefully, the forthcoming public enquiry will reveal some of the answers to these questions, but it reinforces the wise words of my detective mentor and is a lesson for anyone performing the role of an investigator. If you are relying on key technical data or output that seems at odds with your gut instincts around human behaviour or performance, do pursue that second (or third) opinion.

Don't be the silent one in the room and have the courage to voice the question, 'Have we got this right?' This courage can turn a 'critical step' into an effective 'critical stop' for all involved to reorientate and consider whether to continue the current momentum.

About the Author:

Alan Smith

Alan Smith holds the position of Head of Investigations at COMET. Prior to this role, he was a co-founder of Matrix Risk Control (UK) Ltd in 2008. Having served as a Detective Superintendent at Police Scotland, Alan led investigations into significant crimes and multiple offshore fatality incidents in the North Sea Oil and Gas sector.

This experience fuelled Alan's commitment to enhancing performance in this field. In the 12 years since leaving the police force, he has become a recognised expert in incident investigation and root cause analysis training. Alan has conducted numerous programmes in various locations, including the UK, Europe, UAE, Australia, China, and the USA.

After his career in law enforcement, Alan attained accreditation at the Senior Instructor level in both Kelvin TOPSET and TapRooT RCA systems. He has implemented multiple training programmes globally. In 2012, Alan was appointed by a US-based Aerospace Engineering Company to lead a team in developing a customised RCA system called COMET. This system has since become the preferred choice for most operators in the North Sea Oil and Gas sector and is gaining popularity worldwide. Alan's goal was to create a system with proactive applications beyond isolated incidents.

A frequent international conference speaker, Alan shares his expertise on the philosophy of Human and Organisational Performance. He advocates for using Root Cause Learning to foster resilience against human error in organisations.

Investigation Experience

During his final role in law enforcement, Alan led investigations into offshore fatalities and high-profile cases, such as the 2007 capsize of the MV Bourbon Dolphin, resulting in the loss of 5 lives.

In his current position, Alan has been deployed globally to handle various Fatality, Process Safety, and Environmental events. He serves as a lead investigator or RCA facilitator, as exemplified by his recent involvement with a drilling client who experienced two consecutive incidents resulting in three fatalities last year.