Unfair dismissal (constructive) — definition anchored to a real case: Kaur v Leeds (CA, 2018)

William Slivinsky
Sep 25
6 min read

Constructive unfair dismissal definition, last straw, affirmation — DUO presents Kaur v Leeds (CA, 2018) summary on key issues; last straw and affirmation.

If you’re searching for a practical constructive unfair dismissal definition that actually helps in real cases, start with the last straw and affirmation tests. In Kaur v Leeds, the Court of Appeal gives a textbook example: even where there’s a long history of problems, you still need a fresh incident that adds to a cumulative breach—and you must act promptly or risk affirmation by staying.

Crucially, a properly conducted grievance or appeal outcome won’t count as your “last straw,” so don’t resign because an orderly process didn’t go your way. In this UDO guide, we anchor the law to the facts of Kaur and show you how to: spot a real last straw, avoid affirming the contract, tie your resignation to the breach.

Unfair dismissal (constructive) — definition: What you’ll learn in this article

Case snapshot (who, when, what went wrong): A 60-second overview of the facts, timeline, and why Ms Kaur’s dispute reached the courts.
The substance of the enquiry (what the Court actually decided): The precise legal issues the Court of Appeal addressed and how they resolved them.
Constructive unfair dismissal — last straw & affirmation (in one paragraph): A plain-English definition of both concepts and how they interact in real cases.
Why the Court said “no” in Kaur (applied step-by-step): How the five questions were applied to Ms Kaur’s facts and why her claim had no reasonable prospect.
The Kaur roadmap you can lift into any case (5 questions): A reusable checklist to test any constructive dismissal scenario for viability.
How to avoid the same mistakes (practical): Concrete actions to preserve your position—timing, evidence, and framing your resignation.
How to draft and build the last straw on a flawed procedure (based on Ms Kaur’s case) — with template: A fill-in-the-blanks resignation section that turns serious procedural defects into a viable last-straw argument.

Case snapshot (who, when, what went wrong)

Ms Kaur, a nurse at Leeds Teaching Hospitals NHS Trust, said the Trust had subjected her to a course of conduct undermining trust and confidence: persistent and allegedly unjustified performance/capability criticisms, bullying and poor handling of her Dignity at Work complaint, the April 2013 altercation that led to disciplinary proceedings, supposed flaws in the investigation/disciplinary process, and the resulting final written warning (Sept 2013).

She appealed; after a maternity-leave pause, the appeal was dismissed on 16 July 2014, and she resigned the next day, treating the appeal outcome as the “last straw.” The ET struck out her constructive-dismissal claim (no reasonable prospect), and the EAT and Court of Appeal upheld that decision: the tribunal found no arguable wrongdoing in the appeal process, and a properly conducted disciplinary/appeal decision cannot itself be a repudiatory breach or contribute to one—so her last-straw argument failed.

Although Ms Kaur alleged unjustified performance action, bullying and poor grievance handling, the tribunal (on a strike-out footing) gave a high belief to be true and put it all in the most favourable light to her but still rejected the claim: because she had affirmed the earlier events, and her chosen “last straw” (allegation of not properly handling appeal was not well-founded) so couldn’t revive the earlier breaches —so the constructive dismissal case had no reasonable prospect of success.

Tip: If your last straw is a disciplinary, grievance or appeal decision, don’t just argue “unfair outcome.” Identify specific, serious procedural failures that breach policy and/or the ACAS Code and show why they undermined trust and confidence (e.g., bias, key evidence ignored, denial of fair hearing). Trivial or technical breaches won’t count. Note: ACAS Code breaches can justify up to a 25% uplift in awards, but you still must prove a fundamental breach for constructive dismissal.

The substance of the enquiry (what the Court actually decided)

The Court used Ms Kaur’s pleaded facts (because the case was struck out before a full merits hearing) to clarify two linked points:

Affirmation & revival. Even if earlier breaches are affirmed by continuing to work, an employee can still rely on the whole course of conduct if a later incident forms part of that series and isn’t wholly trivial. Taylor Wessing
Nature of the final act. A properly conducted disciplinary/appeal process cannot be a repudiatory breach or contribute to a cumulative breach; so using the appeal dismissal as the “last straw” didn’t work. Strike-out upheld. Menzies Law

Constructive unfair dismissal — last straw & affirmation (in one paragraph)

A last straw is a new incident that, viewed objectively and in context, adds to an ongoing fundamental breach (usually of trust and confidence). It need not be dramatic; it just can’t be wholly trivial or innocuous. Even if earlier breaches were affirmed, a later qualifying act in the same series can revive the right to resign—but a fair, properly handled disciplinary/grievance decision is not that act. Act promptly after the true last straw to avoid further affirmation. Taylor Wessing

Why the Court said no in Kaur (applied step-by-step)

Underhill LJ’s approach maps neatly onto five questions (see below). Applied to Kaur:

Most recent act: the dismissal of her appeal.
Affirmation: earlier matters were effectively affirmed by staying at work.
Repudiatory on its own? No—because the appeal process was properly conducted.
Cumulative breach revived? No—if the latest act isn’t a breach (or is entirely innocuous), it can’t revive the earlier history.
Resignation in response: yes (she resigned the next day), but steps 3–4 were fatal.

The Kaur roadmap you can lift into any case (5 questions)

(1) What is the most recent act you rely on?(2) After it occurred, did you affirm the contract (e.g., by staying on without protest)?(3) Is that act repudiatory on its own?(4) If not, does it add to a cumulative breach that is repudiatory?(5) Did you resign in response to that breach? Taylor Wessing

How to avoid the same mistakes (practical)

Don’t bank on process outcomes as your last straw. A fair disciplinary/grievance decision is unlikely to count. Wait for (or identify) a new incident that actually worsens the breach (e.g., fresh unreasonable treatment), then act or find flawed disciplinary/grievance process not decision. Menzies Law
Time it right. When the real last straw happens, move promptly and tie your resignation to the series plus that final incident. Delay risks affirmation. Taylor Wessing
Paper it properly. Keep a dated chronology; in your resignation say you’re leaving for the employer’s fundamental breach, revived/confirmed by the last straw on [date]. Taylor Wessing

How to Draft and Build the Last Straw on a Flawed Procedure Based on Ms. Kaur's Case with templete

Ms Kaur’s resignation (in substance)

She referred back to the 22 April 2013 incident as “the final straw,” complained generally about unfairness in the investigation and disciplinary process, noted her final written warning (2 Oct 2013), said her appeal was upheld (14/16 July 2014), mentioned her Dignity at Work complaint was still pending, and then resigned, citing a fundamental breach of trust and confidence.

Why that didn’t work

Stale “last straw”. She labelled April 2013 the final straw but resigned in July 2014—this effectively affirmed the earlier events.
No concrete defects. She didn’t pinpoint specific, serious procedural breaches (policy clauses/ACAS Code paragraphs, bias, ignored evidence, refusal of witnesses, etc.). A properly conducted process can’t be a last straw.
Weak causation link. The letter didn’t clearly say: “I resign in response to the employer’s cumulative breach revived by [today’s/this week’s final act].”

How it should be done (if your last straw is a flawed procedure)

Name the fresh act (date of the decision/communication).
Particularise the defects (policy/ACAS Code references + what actually happened).
Tie it to the series (one or two lines listing the earlier incidents).
Causation (explicitly resign in response to the cumulative breach revived by the final act).
Act promptly. Delay risks affirmation.

Template — “Last straw = flawed disciplinary/grievance/appeal”

Notes for readers filling the template

Be specific: Quote policy titles/clauses and ACAS Code paragraphs; attach or reference the documents.
Evidence beats adjectives: Point to witness refusals, ignored documents, predetermination, bias, unreasonable delay that affected fairness.
Keep the chain tight: List only the key earlier events (dates + 3–6 words each).
Timing matters: Send this immediately after the defective outcome (or communication of it).
ACAS uplift ≠ automatic breach: ACAS non-compliance can increase compensation but does not by itself prove a fundamental breach—you still need the defects to be serious enough to destroy trust and confidence.

Primary source & practitioner summaries: Court of Appeal decision in Kaur v Leeds Teaching Hospitals NHS Trust [2018] EWCA Civ 978 (Underhill LJ), with concise practitioner notes on the “last straw”/affirmation guidance.

Have a question?

Pop your scenario in the comments below and I’ll try to help. The more specifics you can share (dates, what happened, what policy/ACAS points you’re relying on, and your draft “last straw” wording), the better the guidance will be. Please avoid posting anything that identifies you or your employer. This page isn’t legal advice, but I can point you to the next practical step.