Introduction
Table of Contents
- Your Burden: Proving the Reason Was Fair
- The Band of Reasonable Responses — Not “Would We Have Done the Same?”
- Building Your Case Around Process, Not Just Outcome
- Common Weak Spots in Employer Defences
- Where Automatic Unfair Dismissal Changes Everything
- Contributory Conduct and Polkey: Reducing Exposure Even If You Lose
- Contact Us for Employment Tribunal Support
- Final Thoughts
- Frequently Asked Questions
Your Burden: Proving the Reason Was Fair
Unlike discrimination claims, where the burden shifts partway through, an unfair dismissal claim puts a specific, upfront burden on you as the employer from the outset: you must show what the reason, or principal reason, for the dismissal actually was, and that it falls within one of five recognised categories — capability, conduct, redundancy, a statutory restriction, or “some other substantial reason.” Failing to clearly establish this at the first hurdle is a genuinely avoidable way to lose a claim that might otherwise have been defensible.
Before analyzing the reason for dismissal, always check the employee’s length of service. An employee generally needs at least two years of continuous service (under s.108 of the Employment Rights Act 1996) to qualify to bring a standard ordinary unfair dismissal claim. If they have under two years of service, the claim can usually be dismissed unless an “automatically unfair” reason applies.
The Band of Reasonable Responses — Not “Would We Have Done the Same?”
Once the reason is established, the tribunal doesn’t ask whether it would have made the same decision itself. It asks whether dismissal fell within the range of responses a reasonable employer could have reached in the circumstances — a genuinely different, and generally more forgiving, question than “was this the objectively correct outcome.” This matters because a defensible dismissal doesn’t need to be the only reasonable one available, just a reasonable one, provided the underlying process was fair.
Building Your Case Around Process, Not Just Outcome
Because the tribunal’s focus is as much on process as on outcome, your defence needs to demonstrate both a genuine reason and a fair way of reaching that decision — proper investigation, a genuine opportunity for the employee to respond, and consistent treatment compared with similar past situations. A dismissal built on a completely genuine, defensible reason can still be found unfair where the process around it was rushed, one-sided, or inconsistent with how comparable situations have previously been handled.
Crucially, failing to comply with the ACAS Code of Practice on Disciplinary and Grievance Procedures carries direct financial penalties. Under s.207A of TULRCA 1992, if an employer unreasonably fails to follow the ACAS Code, tribunals have the power to increase any compensation awarded to the employee by up to 25%.
Common Weak Spots in Employer Defences
The same handful of issues tend to recur. Investigations that reached a conclusion before they were fully complete, decision-makers who weren’t actually independent of the original dispute, inconsistent application of policy between employees in similar situations, and a failure to properly document contemporaneous reasoning all show up repeatedly in unsuccessful defences. None of these require the underlying reason for dismissal to have been wrong — they’re process failures layered on top of what might otherwise have been a defensible decision.
Where Automatic Unfair Dismissal Changes Everything
It’s worth checking early whether the dismissal could fall into one of the automatically unfair categories — reasons connected to whistleblowing, pregnancy, health and safety, or asserting a statutory right, among others. Where this applies, the entire framework above is bypassed: the reasonableness of your process becomes largely irrelevant, and the real question becomes whether the stated reason was truly the principal one, or whether the dismissal was actually connected to a protected reason dressed up as something else. This changes your defensive strategy considerably, since demonstrating a fair process won’t rescue a dismissal where the tribunal finds the real underlying reason was a protected one.
Contributory Conduct and Polkey: Reducing Exposure Even If You Lose
Even where a claim looks likely to succeed, it’s worth understanding that liability and compensation are assessed separately. A tribunal can reduce compensation where the employee’s own conduct contributed to their dismissal, and separately, a Polkey reduction can apply where you can show that a fair process, properly followed, would likely have led to dismissal anyway within a defined period — meaningfully reducing exposure even where the original process fell short. Building well-prepared witness evidence around these points is worth doing from the outset, not as an afterthought once liability looks likely.
Contact Us for Employment Tribunal Support
Whether a dismissal is genuinely defensible often comes down to details in the process — investigation quality, consistency, and documentation — that are worth assessing honestly and early, rather than after a claim has already progressed significantly.
Final Thoughts
Defending an unfair dismissal claim successfully depends on establishing a genuine reason and demonstrating a fair process behind it, not simply on the underlying decision being defensible in principle. Checking early whether an automatically unfair category might apply, and understanding how contributory conduct and Polkey reductions can limit exposure even in a weaker case, both meaningfully shape the right strategy from the outset.
Frequently Asked Questions
Who has the burden of proof in an unfair dismissal claim?
The employer must establish the reason, or principal reason, for the dismissal and show it falls within one of five recognised categories — a different starting position from discrimination claims, where the burden shifts partway through.
What is the band of reasonable responses?
It’s the standard a tribunal applies when assessing whether a dismissal was reasonable — not whether the tribunal itself would have dismissed, but whether the decision fell within the range a reasonable employer could have reached.
Can a genuinely fair reason still result in an unfair dismissal finding?
Yes, if the process around the decision was flawed — inadequate investigation, no genuine opportunity to respond, or inconsistent treatment compared with similar past situations can all undermine an otherwise defensible reason.
What is a Polkey reduction?
It’s a reduction in compensation where an employer can show that a fair process, properly followed, would likely have led to dismissal anyway within a defined period, even where the actual process fell short.
Does automatic unfair dismissal change how I should defend a claim?
Significantly. Where a dismissal might fall into an automatically unfair category, the reasonableness of your process becomes largely irrelevant, and the focus shifts to whether the stated reason was genuinely the true one.
Can an employee's own conduct reduce compensation even if I lose?
Yes. A tribunal can reduce compensation where the employee’s actions contributed to their dismissal, separate from the question of whether the dismissal itself was fair.