Read enough employment tribunal judgments and you stop seeing variety. The same handful of failures come up again and again, across industries, across company sizes, in businesses run by decent people who thought they were doing the right thing.
Here are the five that cost the most, and what each one actually takes to fix.
In short:
- Nearly all of these are process failures, not judgement failures.
- The employer is often right about the substance and loses anyway.
- Every fix is cheap. Losing is not.
1. Dismissing without a process
The most expensive mistake, and the most common.
A fair reason to dismiss is only half the legal test. The other half is whether you acted reasonably in how you did it: did the person know what the problem was, did they get a real chance to respond, was the decision explained, could they appeal?
Employers lose this one constantly while being entirely right about the underlying problem. We covered a case where a company dismissed its own chief executive for genuine performance failures, skipped its own procedure, and was found to have dismissed him unfairly. Read what happened in Zen Internet v Stobart.
The fix: write down your minimum steps and follow them every time. Concern in writing, meeting, chance to respond, written decision, right of appeal. Weeks, not months.
2. Having a policy you do not follow
This one has a cruel edge to it. If you have a disciplinary procedure and ignore it, that failure is itself evidence of unfairness. Your own document becomes the standard you are measured against and the proof you fell short of it.
The Acas Code of Practice on disciplinary and grievance procedures makes it worse. Where an employer unreasonably fails to follow it, a tribunal can increase compensation by up to 25 per cent.
The fix: read your own policies. If you would not realistically follow them, either commit to following them or rewrite them into something you would.
3. Treating the paperwork as admin
Most owners think of employment documents as bureaucracy: something to get out of the way at the start and forget.
At tribunal, those documents are the evidence. The contract that says what hours someone works. The written statement of particulars that is a legal requirement from day one. The dated note of the meeting where you raised a concern. Without them, the case comes down to your recollection against theirs, months later, in front of someone with no reason to prefer either.
The side with contemporaneous records usually wins the factual disputes. Not because they are more honest, but because they can show their working.
The fix: one folder per employee, and a habit of writing things down on the day rather than the week after.
4. Assuming short service means no risk
The old rule of thumb was that employees needed two years' service before they could claim unfair dismissal, so new hires were low risk.
That rule is going. From January 2027 the qualifying period drops from 2 years to 6 months, and the cap on compensatory awards is removed. Meanwhile some claims never needed any qualifying service at all: discrimination, whistleblowing, and dismissals connected to statutory rights can be brought from day one, by anyone.
The fix: stop treating length of service as a safety net, and run the same process for a six-month employee as for a ten-year one.
5. Letting the clock lull you
Employers have always had a rough sense that after a few months, a departure stops being a risk.
From 1 October 2026 that window doubles: most tribunal claims can be brought up to 6 months after the event rather than 3. Every dismissal, redundancy and resignation now carries live risk for twice as long, and the hearing itself may be a year further on again. See what the new time limits mean in practice.
The fix: keep records well beyond the point where you think the risk has passed, and make sure someone other than you could find them.
What these five have in common
Not one of them requires legal expertise to avoid. They require doing ordinary things in a particular order and writing them down.
That is precisely what gets skipped in a business where the person handling employment matters is also handling sales, invoicing, and the actual work. Not through carelessness, but because paperwork loses to whatever is urgent, every single time, until the day it is the only thing that matters.
What to do this week
- Pick your three most recent employment decisions. Could you produce the documents behind each one today?
- Read your own disciplinary procedure and decide whether you would actually follow it.
- Check that anyone who manages people knows the minimum steps.
- Diarise January 2027, when unfair dismissal rights start at 6 months' service.
This article explains UK employment law in plain English. It is general information, not legal advice. For advice on your specific situation, speak to a solicitor.