ACAS Tribunal Cases – Why Fairness Matters More

ACAS Tribunal Cases is an UDO series on how to frame breaches of the ACAS Code of Practice into your claim for unfair dismissal. The aim is to help you understand why procedure alone is rarely enough, and how tribunals actually decide these cases under s.98(4) ERA 1996. To get the full picture, you should read this series alongside our other guides: [Disciplinary Step-by-Step Guide] and [Disciplinary Outcomes – Guide].

ACAS Tribunal Cases and their Limits

What the law says: The ACAS Code sets minimum standards for disciplinary and grievance procedures. If your employer ignores it, a tribunal can increase (or reduce, if it’s you who failed to comply) compensation by up to 25%. This is what most employees don’t understand — they wrongly think that ACAS alone determines unfair dismissal.

In practice: Not following the ACAS Code doesn’t automatically make a dismissal unfair. The tribunal still looks at whether your employer had a fair reason and acted reasonably under s.98(4) ERA 1996. The key is to show that the failure to follow the ACAS Code turned into an unreasonable response and led to inadequate (whether deliberate or careless) grounds for dismissal at the material time. In this article, I’ll explain how to frame ACAS Code failures as an omission to consider your health and safety defence under s.2 HSWA 1974 — with one of the most common examples being leaving your job because of a stressful work environment.

📌 Practical tip: Use ACAS breaches as supporting evidence, not the centrepiece of your case. Show how those breaches link to unfairness — for example, you weren’t given a chance to answer allegations. If that happened, the employer’s decision was based on flawed and inadequate evidence. Even if the “missing” evidence later comes out at tribunal, the employer may still fail the s.98(4) test because fairness is judged on what they knew at the time of dismissal, not what comes out later.

📌 Note: Conversely, even if your employer followed the ACAS Code to the letter, that doesn’t always make a dismissal fair. In another article in this series, I’ll explain how the Burchell and Iceland tests work — and why tribunals still look at the reasonableness of the investigation and the employer’s response under s.98(4) ERA 1996.

The Polkey Principle

What the law says: In Polkey v AE Dayton Services Ltd [1987], the House of Lords said a dismissal can still be fair even if procedure was flawed — if the tribunal believes dismissal would have happened anyway.

In practice: Tribunals often reduce compensation if they think dismissal was inevitable. They will only award what you would have earned in the short extra time a fair process would have taken (sometimes just one or two weeks). So, if you frame your case only around the ACAS Code, you may walk away with just a week or two of lost income. The tribunal may decide that this was the time your employer needed to dismiss you properly — meaning you fail the test of reasonable responses under s.98(4) ERA 1996.

📌 Practical tip: Don’t just focus on procedure. Gather evidence to show that a reasonable employer might not have dismissed you at all. Start with the outcome letter. If it doesn’t explain why alternatives weren’t suitable, argue they weren’t considered — something a reasonable employer wouldn’t omit. If it does mention alternatives, check whether the reasons given line up with the disciplinary policy. Any inconsistency can be powerful evidence of unfairness.

Section 98(4) ERA 1996 — Fairness and Safety at Work

What the law says: Section 98(4) ERA requires tribunals to decide whether dismissal was reasonable “in all the circumstances.” It’s not enough for your employer to point to a reason — the tribunal looks at whether dismissal was a proportionate and fair response. Linked to this, section 2 HSWA 1974 requires employers to provide a safe and healthy workplace, which includes protecting employees from psychological risks such as stress and bullying, not just physical hazards.

In practice: Even if your employer failed to follow ACAS procedures, you could still lose your case if the tribunal decides that any reasonable employer would have dismissed you anyway. This is particularly common in conduct cases, such as accusations of insubordination or walking out. At UDO, we often see employees leave the workplace because of bullying, overwork, or frustration at management’s inaction. They leave their work, go to the GP, get a sick note, and then face disciplinary action when they return. The mistake employees make is focusing only on the frustration itself. The stronger argument is to frame the issue as one of safety and welfare: if your working conditions were unsafe, unhealthy, or posed risks to others, the employer had a legal duty to take that into account. Remember, stress in certain types of work is a valid health and safety concern.

📌 Practical tip: Frame your case around fairness and safety, not just procedure. Ask: “Would another reasonable employer have done the same?” For example, if you were accused of leaving work without permission, but you did so because conditions were unsafe, your employer should have considered your defence under s.2 HSWA 1974. If the outcome letter, investigation report, or hearing minutes show no consideration of those risks, you can argue that dismissal wasn’t just procedurally flawed — it was an unreasonable response under s.98(4) ERA 1996. This is especially powerful in safety-sensitive roles (drivers, forklift operators, machinery). Stress and overwork in those jobs don’t just affect you — they can endanger others. If your employer ignored that reality, the fairness test under s.98(4) may not be satisfied.

When Employees Don’t Follow the Code

What the law says: The ACAS Code isn’t just for employers. Tribunals can reduce awards by up to 25% if employees don’t follow it — for example, by skipping an internal appeal. This is why UDO has created the series called  [Disciplinary Step-by-Step Guide] and [Disciplinary Outcomes – Guide].

In practice: If you don’t appeal, tribunals may cut your award to almost nothing. Sometimes you end up with only a recommendation of wrongdoing, but no money.

📌 Practical tip: Always appeal. Even if you think it’s pointless, it protects your claim and prevents the tribunal from cutting your compensation.

Lessons You Can Take Away

1. ACAS breaches help but aren’t enough. Use them to show gaps in fairness, not as the main argument.

2. Expect the Polkey question. Be ready to argue why dismissal wasn’t inevitable.

3. Focus on s.98(4). Show why dismissal wasn’t a reasonable response in your circumstances.

4. Read the outcome letter closely. Spot omissions or inconsistencies about alternatives and use them.

5. Use your appeal rights. Don’t hand the employer a reduction in your award.

6. Frame absences as safety issues. Stress, bullying, or overwork can fall under s.2 HSWA 1974 — not just frustration.

   
   

Final Thoughts

Tribunals don’t hand out big awards just because an employer tripped up on the ACAS Code. The real question is whether dismissal was fair and reasonable under s.98(4) ERA 1996. That’s why focusing only on procedure is risky.

By linking ACAS breaches to fairness, challenging outcome letters, and framing your case around safety and well-being, you put yourself in the strongest possible position.