By Tim Smith, Head of Investigations at Safecall
Workplace investigations have never mattered more. Reports of misconduct and workplace concerns are rising steadily, and the data backs that up. At Safecall, our whistleblowing hotline and web reporting platform is used by more than 1,200 organisations representing over six million people worldwide. In our latest Benchmark Report, we found that the rate of reports has increased from one for every 520 employees in 2020 to one for every 365 employees in 2025. That is a significant shift in a short space of time.
With more reports – inevitably – comes more investigations. And alongside that, Employment Tribunal cases are rising fast, giving employers every reason to ensure their investigation processes are not just thorough, but defensible.
When a workplace investigation is handled well, it does more than resolve the immediate concern. It protects the business, yes – but it also protects the people involved: the person who raised the concern, the person accused, and anyone else who plays a part in the process. Done well, an investigation sends a clear message that the organisation takes these matters seriously and handles them fairly. It builds trust, and that trust is hard to win back once it is lost.
A poorly handled investigation, on the other hand, can cause serious damage – to individuals, to organisational culture, and to legal standing. In my experience, the same mistakes come up time and again. Here are the three I see most often.
Mistake 1: appointing the wrong investigator
You can conduct a technically flawless investigation – thorough, methodical, well-documented – and still have the whole thing fall apart if the wrong person is leading it.
The appointment of the investigator is, in my view, the single most important decision in the entire process. And it is also one of the most commonly overlooked.
The key question is independence. Whoever conducts the investigation must be demonstrably independent from the concern being investigated. That means thinking carefully about conflicts of interest, reporting lines, and organisational hierarchies. Does the investigator have a prior relationship with the complainant or the accused? Do they sit within the same team or business unit? Would a reasonable, objective observer question their neutrality?
These are not just procedural niceties. They are exactly the kinds of questions that get asked at Employment Tribunals – and they do get challenged. I have seen well-run investigations discredited not because of how they were conducted, but because of who conducted them.
One practical step I would always recommend is obtaining a statement from all relevant parties confirming that they have no conflict of interest with the investigator. It takes very little time and adds a meaningful layer of protection.
The bottom line: before you even begin, ask yourself whether the appointment of this investigator can withstand scrutiny from the outside. If you have any doubt, address it.
Mistake 2: failing to justify constraints on the investigation
One of the most common phrases I hear in investigation reviews is: “We couldn’t speak to that employee because they had left the organisation.” I understand why this happens – but saying it without any further justification is a significant problem.
Every investigation operates within a scope, and there will always be constraints. Former employees, unavailable witnesses, documents that no longer exist – these are realities. The mistake is not encountering them. The mistake is failing to address them properly.
When an external reviewer – whether that is an Employment Tribunal, a legal team, or an independent auditor – looks at your investigation, they will ask why certain individuals were not interviewed. They will note that the investigation might have benefited from speaking to the former employee. If you cannot explain why that conversation did not happen, or demonstrate that its absence did not affect the impartiality of your findings, you are in a difficult position.
The answer is to be robust in your terms of reference from the outset. Define your scope clearly. And where constraints exist, document them – explain what they are, why they arose, and why you are satisfied that the investigation remains fair and impartial despite them. If a constraint genuinely calls impartiality into question, that needs to be addressed before you proceed, not explained away after the fact.
The bottom line: never stray outside your terms of reference, but always be able to justify the boundaries you have set and the limitations you have worked within.
Mistake 3: getting proportionality wrong
This one cuts in both directions – and both directions can cause real problems.
Workplace investigations often fall to HR professionals, sometimes with limited investigation experience, handling it alongside their day-to-day responsibilities. Or they fall to line managers who are even less prepared. In those situations, it is easy for the investigation to go one of two ways.
The first is under-investment: the investigation is rushed, corners are cut, and the person leading it begins to feel that the whole exercise is a burden rather than a responsibility. That attitude tends to show in the quality of the work.
The second – and in my experience, the more common pitfall – is over-reaction. A well-meaning investigator, worried about getting things wrong or being criticised, feels compelled to go far deeper than the situation warrants. They expand the scope, interview more people than necessary, and spend far more time on the matter than it deserves. The result is an investigation that is disproportionate to the concern, which creates its own problems, not least for the individuals involved and for the organisation’s time and resource.
There is an important distinction here between being defensive and being defensible. A defensible investigation is one that is proportionate, well-scoped, and clearly reasoned. A defensive investigation is one that does too much in the hope of covering every possible angle, and often ends up less focused and less credible as a result.
My advice is to always have a second set of eyes on an investigation – a critical friend, whether that is HR, a senior colleague, or an external specialist. Agree your scope before you begin, and build in a checkpoint before extending it. You can always go further if you need to, but it is much harder to scale back once you are in the middle of things.
The bottom line: match the depth of the investigation to the seriousness of the concern. Not every report requires a full-scale inquiry. Proportionality is not a shortcut – it is good practice.
Final thought
Workplace investigations are genuinely difficult, and the stakes are high. Whether you are an experienced HR professional, a senior leader with accountability for how these matters are handled, or a line manager facing your first investigation, the pressure to get it right is real.
What gives me confidence – and what I hope gives you confidence – is that the most common mistakes are also the most preventable. Appoint the right investigator. Justify your scope. Get the proportionality right. And do not be afraid to ask for help.
At Safecall, we support organisations at every stage of the process. If you would like to understand how we can help with your investigation support needs, or if you want to see the full findings from our latest Benchmark Report – including the data on rising report rates and what it means for employers – we are always here to help.
About the author: Tim Smith
Tim Smith is Head of Investigations at Safecall, one of the UK’s leading whistleblowing and workplace investigation providers. Safecall works with more than 1,200